Complementary Angles

Two Angles are Complementary if they add up to 90 degrees (a Right Angle).

These two angles (40° and 50°) areComplementary Angles, because they add up to 90°. Notice that together they make a right angle.
But the angles don't have to be together. These two are complementary because 27° + 63° = 90°

Sumber : http://www.mathsisfun.com/geometry/complementary-angles.html

Read More

Supplementary Angles

Two Angles are Supplementary if they add up to 180 degrees.

These two angles (140° and 40°) are Supplementary Angles, because they add up to 180°. Notice that together they make a straight angle.
But the angles don't have to be together. These two are supplementary because 60° + 120° = 180°

Sumber :  http://www.mathsisfun.com/geometry/supplementary-angles.html

Read More

Polygons

A polygon is a plane shape with straight sides.

Is it a Polygon?

Polygons are 2-dimensional shapes. They are made of straight lines, and the shape is "closed" (all the lines connect up).

Polygon (straight sides)	Not a Polygon (has a curve)	Not a Polygon (open, not closed)

Polygon comes from Greek. Poly- means "many" and -gon means "angle".

Types of Polygons

Simple or Complex

A simple polygon has only one boundary, and it doesn't cross over itself. A complex polygon intersects itself!

Read More

Sets and Venn Diagrams

Sumber : http://www.mathsisfun.com/sets/venn-diagrams.html

Sets

A set is a collection of things. For example, the items you wear is a set: these would include shoes, socks, hat, shirt, pants, and so on. You write sets inside curly brackets like this: {socks, shoes, pants, watches, shirts, ...}

You can also have sets of numbers:

• Set of whole numbers: {0, 1, 2, 3, ...}
• Set of prime numbers: {2, 3, 5, 7, 11, 13, 17, ...}

Ten Best Friends

You could have a set made up of your ten best friends:

• {alex, blair, casey, drew, erin, francis, glen, hunter, ira, jade}

Each friend is an "element" (or "member") of the set (it is normal to use lowercase letters for them.)

Now let's say that alex, casey, drew and hunter play Soccer:

Soccer = {alex, casey, drew, hunter}

(The Set "Soccer" is made up of the elements alex, casey, drew and hunter).

And casey, drew and jade play Tennis:

Tennis = {casey, drew, jade}

You could put their names in two separate circles:

Read More

Algebraic Number

Algebraic Number

An algebraic number is any number that is a root of a non-zero polynomial with rationalcoefficients.

Put more simply, when you have a polynomial like (for example):

2x² - 4x + 2 = 0

Then x is algebraic.

Because:

• It is a non-zero polynomial
• x is a root (ie x gives the result of zero for the function 2x² - 4x + 2)
• the coefficients (the numbers 2, 4 and 2) are rational numbers

The polynomial could, of course, be simpler or more complicated than this example, just so long as the coefficents are rational.

Read More

Circle

A circle is easy to make: Draw a curve that is "radius" away from a central point. And so: All points are the same distance from the center.

You Can Draw It Yourself Put a pin in a board, put a loop of string around it, and insert a pencil into the loop. Keep the string stretched and draw the circle!

Read More

Angle

Names of Angles

As the Angle Increases, the Name Changes

Type of Angle	Description
Acute Angle	an angle that is less than 90°
Right Angle	an angle that is 90° exactly
Obtuse Angle	an angle that is greater than 90° but less than 180°
Straight Angle	an angle that is 180° exactly
Reflex Angle	an angle that is greater than 180°

Read More