8/17/2019 MATH 005 7.1 Angles (Part 1)

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MATH 005 – Mr. Hao-Nhien Vu – 7.1 Angles (part 1)

Geometry is the branch of mathematics that deals with figures in space, such as:

A ________. A ________ is straight and extends indefinitely in both directions.

A portion of a line is called a _________________________________. A line segment has twoendpoints.

A part of a line that has only one endpoint and goes on forever in one direction is called a __________.

Two rays that start at a common endpoint form an _________________.

The two rays are called the ____________ of the angle.

The point where the two rays meet is its ______________.

How big the angle “opens” can be measured, commonly in ______________, symbol _____. We oftenmark the opening with a little curve.

Important degree measures

A complete revolution: _______

A half revolution is when the sides line up

(a _____________ angle): ________

A quarter revolution

(a _____________ angle): ________

If two line form a 90 o angle, they are ______________________.

We usually mark a square angle with a small square symbol.

8/17/2019 MATH 005 7.1 Angles (Part 1)

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Naming an angle using the angle symbol ∠

Suppose we have this angle.

We can call it by the vertex:

We can call it by a letter or number inside the angle.

We can call it by the three points that allow us to draw the angle:

In that case, the ________________ letter is the vertex.

Using the vertex alone can be confusing when that point is the vertex of many angles.

Ex. 1. Name the two small angles in this figure. Also name the la rge angle that’s covering the whole thing.

Types of angle

A 180 o angle is called a ____________________ angle.

A 90o

angle is called a _____________________ angle.

An angle that’s smaller than 90 o (pointy looking) is called an ________________ angle.

An angle that’s larger than 90 o and less than 180 o is called an _________________ angle.