Tuesday, October 20, 2009
Monday, July 13, 2009
Polygon Basic
The table lists all the polygons having up to 10 sides.
The word polygon is a combination of two Greek words: "poly" means many and "gon" means angle. Along with its angles, a polygon also has sides and vertices. "Tri" means "three," so the simplest polygon is called the triangle, because it has three angles. It also has three sides and three vertices. A triangle is always coplanar, which is not true of many of the other polygons.
A regular polygon is a polygon with all angles and all sides congruent, or equal. Here are some regular polygons.
We can use a formula to find the sum of the interior angles of any polygon. In this formula, the letter n stands for the number of sides, or angles, that the polygon has.
sum of angles = (n – 2)180°
Let's use the formula to find the sum of the interior angles of a triangle. Substitute 3 for n. We find that the sum is 180 degrees. This is an important fact to remember.
sum of angles = (n – 2)180°
= (3 – 2)180° = (1)180° = 180°
To find the sum of the interior angles of a quadrilateral, we can use the formula again. This time, substitute 4 for n. We find that the sum of the interior angles of a quadrilateral is 360 degrees.
sum of angles = (n – 2)180° = (4 – 2)180° = (2)180° = 360°
Polygons can be separated into triangles by drawing all the diagonals that can be drawn from one single vertex. Let's try it with the quadrilateral shown here. From vertex A, we can draw only one diagonal, to vertex D. A quadrilateral can therefore be separated into two triangles.
If you look back at the formula, you'll see that n – 2 gives the number of triangles in the polygon, and that number is multiplied by 180, the sum of the measures of all the interior angles in a triangle. Do you see where the "n – 2" comes from? It gives us the number of triangles in the polygon. How many triangles do you think a 5-sided polygon will have?
Here's a pentagon, a 5-sided polygon. From vertex A we can draw two diagonals which separates the pentagon into three triangles. We multiply 3 times 180 degrees to find the sum of all the interior angles of a pentagon, which is 540 degrees.
sum of angles = (n – 2)180° = (5 – 2)180° = (3)180° = 540°
Sunday, April 12, 2009
Online Competition on Mathematic subjects taken by Form1 students
Dear teachers and students,
The College of Engineering, UNITEN, is organizing an Online Competition on various subjects taken by Form1 students. At the moment, the online competition for Form1 Mathematics is opened to be participated by the students. The prizes are as follows:
1st Prize: Cash RM100
2nd Prize: Cash RM 75
3rd Prize: Cash RM 50
The top 20 will also receive the certificate of participation from the College of Engineering, UNITEN.
The students need to register at the following website in order to participate in the competition:
http://coe3.uniten.edu.my/COE/school_login.php
We hope you can inform and encourage the Form1 students at your school to participate in this online competition. We have selected your school because many of UNITEN students were from from this school.
Assoc. Prof. Dr. Mohd Azree Idris
Deputy Dean (Student Affairs and External Links)
College of Engineering
UNITEN
Arahan:
1. Anda perlu mendaftar di alamat berikut:
http://coe3.uniten.edu.my/COE/school_login.php
2. Username dan Password akan dihantar ke emai anda. Oleh itu anda diminta menggunakan email sekolah iaitu:
http://partnerpage.google.com/smach.edu.my
3. Setelah mendapat username & Password anda boleh bertanding dengan menggunakan alamat di arahan 1.
Selamat mencuba.
View Ranking on 19 April 2009
No ID School
1. J000042 251.9991 SEKOLAH MENENGAH SAINS MACHANG
2. J000061 225.9990 SEKOLAH MENENGAH SAINS MACHANG
3. J000026 218.9995 SEKOLAH MENENGAH MAAHAD MUHAMMADI (PEREMPUAN)
4. J000002 180.9998 SEK. MEN. KEBANGSAAN JALAN TIGA, BANGI, SELANGOR
5. J000118 160.9989 SEKOLAH MENENGAH SAINS MACHANG
6. J000038 144.9991 SEKOLAH MENENGAH SAINS MACHANG
7. J000079 140.9992 SEKOLAH MENENGAH SAINS MACHANG
8. J000077 113.9991 SEKOLAH MENENGAH SAINS MACHANG
9. J000059 90.9994 SEKOLAH MENENGAH SAINS MACHANG
10. J000069 60.9995 SEKOLAH MENENGAH SAINS MACHANG
11. J000044 55.9997 SEKOLAH MENENGAH SAINS MACHANG
12. J000082 47.9999 SEKOLAH MENENGAH SAINS MACHANG
13. J000062 45.9996 SEKOLAH MENENGAH SAINS MACHANG
14. J000049 43.9996 SEKOLAH MENENGAH SAINS MACHANG
15. J000091 41.9996 SEKOLAH MENENGAH SAINS MACHANG
View Ranking on 26 April 2009
No ID School
1. J000026 289.9990 SEKOLAH MENENGAH MAAHAD MUHAMMADI (PEREMPUAN)
2. J000042 287.9989 SEKOLAH MENENGAH SAINS MACHANG
3. J000061 287.9987 SEKOLAH MENENGAH SAINS MACHANG
4. J000038 189.9987 SEKOLAH MENENGAH SAINS MACHANG
5. J000118 184.9987 SEKOLAH MENENGAH SAINS MACHANG
6. J000002 180.9998 SEK. MEN. KEBANGSAAN JALAN TIGA, BANGI, SELANGOR
7. J000144 180.9982 SEK AGAMA SAMSUL MAARIF (PULAU CHONDONG)
8. J000079 170.9989 SEKOLAH MENENGAH SAINS MACHANG
9. J000077 119.9990 SEKOLAH MENENGAH SAINS MACHANG
10. J000059 90.9994 SEKOLAH MENENGAH SAINS MACHANG
11. J000044 77.9994 SEKOLAH MENENGAH SAINS MACHANG
12. J000069 60.9995 SEKOLAH MENENGAH SAINS MACHANG
13. J000062 52.9996 SEKOLAH MENENGAH SAINS MACHANG
14. J000082 47.9999 SEKOLAH MENENGAH SAINS MACHANG
15. J000155 45.9994 SEKOLAH MENENGAH SAINS MACHANG
4 mei 2009
View Ranking
No ID School
1. J000042 300.9989 SEKOLAH MENENGAH SAINS MACHANG
2. J000026 300.9989 SEKOLAH MENENGAH MAAHAD MUHAMMADI (PEREMPUAN)
3. J000061 299.9986 SEKOLAH MENENGAH SAINS MACHANG
4. J000144 299.9971 SEK AGAMA SAMSUL MAARIF (PULAU CHONDONG)
5. J000155 256.9973 SEKOLAH MENENGAH SAINS MACHANG
6. J000079 218.9985 SEKOLAH MENENGAH SAINS MACHANG
7. J000038 218.9983 SEKOLAH MENENGAH SAINS MACHANG
8. J000118 215.9984 SEKOLAH MENENGAH SAINS MACHANG
9. J000002 186.9997 SEK. MEN. KEBANGSAAN JALAN TIGA, BANGI, SELANGOR
10. J000044 162.9984 SEKOLAH MENENGAH SAINS MACHANG
11. J000077 131.9989 SEKOLAH MENENGAH SAINS MACHANG
12. J000059 109.9992 SEKOLAH MENENGAH SAINS MACHANG
13. J000062 95.9990 SEKOLAH MENENGAH SAINS MACHANG
14. J000069 81.9992 SEKOLAH MENENGAH SAINS MACHANG
15. J000082 68.9996 SEKOLAH MENENGAH SAINS MACHANG
13 Mei 2009
View Ranking
No ID School
1. J000144 319.9971 SEK AGAMA SAMSUL MAARIF (PULAU CHONDONG)
2. J000026 313.9989 SEKOLAH MENENGAH MAAHAD MUHAMMADI (PEREMPUAN)
3. J000042 313.9988 SEKOLAH MENENGAH SAINS MACHANG
4. J000061 313.9986 SEKOLAH MENENGAH SAINS MACHANG
5. J000155 280.9970 SEKOLAH MENENGAH SAINS MACHANG
6. J000079 233.9983 SEKOLAH MENENGAH SAINS MACHANG
7. J000038 218.9983 SEKOLAH MENENGAH SAINS MACHANG
8. J000118 215.9984 SEKOLAH MENENGAH SAINS MACHANG
9. J000002 190.9997 SEK. MEN. KEBANGSAAN JALAN TIGA, BANGI, SELANGOR
10. J000044 162.9984 SEKOLAH MENENGAH SAINS MACHANG
11. J000077 131.9989 SEKOLAH MENENGAH SAINS MACHANG
12. J000059 109.9992 SEKOLAH MENENGAH SAINS MACHANG
13. J000062 95.9990 SEKOLAH MENENGAH SAINS MACHANG
14. J000069 81.9992 SEKOLAH MENENGAH SAINS MACHANG
15. J000082 68.9996 SEKOLAH MENENGAH SAINS MACHANG
26 Jun 2009 11.00 AM
View Ranking
No ID School
1. J000026 339.9988 SEKOLAH MENENGAH MAAHAD MUHAMMADI (PEREMPUAN)
2. J000144 339.9970 SEK AGAMA SAMSUL MAARIF (PULAU CHONDONG)
3. J000042 337.9988 SEKOLAH MENENGAH SAINS MACHANG
4. J000061 333.9985 SEKOLAH MENENGAH SAINS MACHANG
5. J000079 330.9975 SEKOLAH MENENGAH SAINS MACHANG
6. J000155 305.9969 SEKOLAH MENENGAH SAINS MACHANG
7. J000002 264.9989 SEK. MEN. KEBANGSAAN JALAN TIGA, BANGI, SELANGOR
8. J000118 236.9982 SEKOLAH MENENGAH SAINS MACHANG
9. J000038 226.9982 SEKOLAH MENENGAH SAINS MACHANG
10. J000062 195.9977 SEKOLAH MENENGAH SAINS MACHANG
11. J000044 163.9983 SEKOLAH MENENGAH SAINS MACHANG
12. J000082 153.9984 SEKOLAH MENENGAH SAINS MACHANG
13. J000059 144.9987 SEKOLAH MENENGAH SAINS MACHANG
14. J000077 136.9988 SEKOLAH MENENGAH SAINS MACHANG
15. J000069 112.9988 SEKOLAH MENENGAH SAINS MACHANG
Soalan akhir-akhir ini mudah tetapi jawapannya tidak membantu meningkatkan kedudukan pelajar dalam rangking. Setelah berbincangan dengan pelajar tentang jawapan yang diberikan, nyata jawapan tersebut adalah betul.
Contoh:
A farmer needs 30 pieces of woods with the length of 3 m 75 cm each to build a chicken coop. Find length of wood needed.
Jawapan: 30 pieces * 375 m = 112.50 meter atau 112.50 m
Iwani has 10 m of green thread and 45 m of yellow thread. She needs 10 pieces of green thread with the length of 55 cm each and 10 pieces of yellow thread with the length of 40 cm each to embroiders as many handkerchiefs. What is the total length of the thread left, in m?
Jawapan: 1000 cm - (10 * 55)cm + 4500 cm - (10 * 40) cm = (1000 - 550) + (4500 - 400)
= 45.50 m
Wednesday, April 8, 2009
Integer
Two integers that are the same distance from zero in opposite directions are called opposites.
Every integer on the number line has an absolute value, which is its distance from zero.
. An integer with the plus sing (+) ia a positive integer. It is normally written without the sign (+). For example, +6 or 6 is read as positive six or six.
. An integer with the nibus sign(-) is anegative integer. For example, -24 is read as negative twenty-four.
Use the number line for adding and subtracting integers:
* Add a positive integer by moving to the right on the number line
* Add a negative integer by moving to the left on the number line
* Subtract an integer by adding its opposite
Try it by clicking on the problems below.
Watch out! The negative of a negative is the opposite positive number. That is, for real numbers, - (- a ) = + a
We can use the number line as a model to help us visualize adding and subtracting of signed integers. Just think of addition and subtraction as directions on the number line. There are also several rules and properties that define how to perform these basic operations.
To add integers having the same sign, keep the same sign and add the absolute value of each number.
To add integers with different signs, keep the sign of the number with the largest absolute value and subtract the smallest absolute value from the largest.
Subtract an integer by adding its opposite.
Watch out! The negative of a negative is the opposite positive number. That is, for real numbers,
-(-a) = +a
Here's how to add two positive integers:
4 + 7 = ?
If you start at positive four on the number line and move seven units to the right, you end up at positive eleven. Also, these integers have the same sign, so you can just keep the sign and add their absolute values, to get the same answer, positive eleven.
Here's how to add two negative integers:
-4 + (-8) = ?
If you start at negative four on the number line and move eight units to the left, you end up at negative twelve. Also, these integers have the same sign, so you can just keep the negative sign and add their absolute values, to get the same answer, negative twelve.
Here's how to add a positive integer to a negative integer:
-3 + 6 = ?
If you start at negative three on the real number line and move six units to the right, you end up at positive three. Also, these integers have different signs,
so keep the sign from the integer having the greatest absolute value and subtract the smallest absolute value from the largest.
Subtract three from six and keep the positive sign, again giving positive three.
Here's how to add a negative integer to a positive integer:
5 + (-8) = ?
If you start at positive five on the real number line and move eight units to the left, you end up at negative three. Also, these integers have different signs, so keep the sign from the integer having the greatest absolute value and subtract the smallest absolute value from the largest, or subtract five from eight and keep the negative sign, again giving negative three.
To subtract a number, add its opposite:
5 - 8 = ?
Because they give the same result, you can see that subtracting eight from five is equivalent to adding negative eight to positive five. The answer is - 3.
To subtract a number, add its opposite:
-3 - (-6) = ?
Because they give the same result, you can see that subtracting negative six from negative three is equivalent to adding positive six to negative three. The answer is 3.
