Classifying Angles

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Mathematics Geometry Classifying Angles

	Classifying Angles
	An angle is a portion of two-dimensional plane which is formed, when two rays emanate from a point. The starting point of the angle is known as the initial side and the ending position of the angle is known as the terminal side. The point from which both of the directed line segments originate is known as the vertex of the angle. Angles are measured in degrees. A degree is a fraction of a circle—there are 360 degrees in a circle, represented like this: 360⁰. The right angle is the most common angle—that represents one-fourth of a circle. 360⁰ divided by 4 equals 90⁰. A straight angle represents half of a circle. 360⁰ divided by 2 equals 180⁰—that is the measure of a straight angle. An acute angle is any angle that measures less than 90⁰. An obtuse angle measures greater than 90⁰ but less than 180⁰. Two angles that have the same measure are called congruent angles. Here are two angles that both measure 30⁰. We say that angle x is congruent to angle y. Two angles are called supplementary if their measures add up to 180⁰. These two 90⁰ angles are supplementary because 90⁰ + 90⁰ = 180⁰. 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°. A pair of angles is called complementary if their measurements add up to 90⁰. These two angles are complementary, because 60⁰ + 30⁰ = 90⁰.