Download 1 - Wall ISD

1.3
Objectives
Name and classify angles.
Measure and construct angles and angle bisectors.
An angle is a figure formed by ______ ______, or sides, with a common
__________ called the _______________(plural: vertices). You can name an angle
several ways:
1.
2.
3.
The set of all points between the sides of the angle is the _______________
_________________. The exterior of an angle is _____________________________
_________________________________________________________________________.
What are all of the names to this angle?

Example 1A
A surveyor recorded the angles formed by a transit (point A) and three distant
points, B, C, and D. Name three of the angles.

Example 1B
Write the different ways you can name the angles in the diagram.
Remember: when naming an angle using three letters,
the center letter should ALWAYS be the vertex!!!
The measure of an angle is usually given in ________________.
If OC corresponds with c and OD corresponds with d, mDOC = |d – c| or |c – d|.
Types of Angles:
Acute
Between o˚ and 90˚

Right
90˚
Obtuse
Between 9o˚ and 180˚
Straight
180˚
Example 2
Find the measure of each angle. Then classify each as acute, right, or obtuse.
a) WXV
b) ZXW
Congruent angles are angles that have the ____________ _____________________.
In the diagram ABC = mDEF, so you can write ABC  DEF. This is read
as “________________________________________________________________________.”
___________ ____________ are used to show that the two angles are congruent.
ANGLE ADDITION POSTULATE
If S is in the interior of PQR, then mPQS + mSQR = mPQR

Example 3A
mDEG = 115°, and mDEF = 48°. Find mFEG

Example 3B
mXWZ = 121° and mXWY = 59°. Find mYWZ.
An angle bisector is a ray that ______________an angle into two
______________ ___________________.
JK bisects LJM; thus _________________________

Example 4A
KM bisects JKL, mJKM = (4x + 6)°, and mMKL = (7x – 12)°. Find mJKM.

Example 4B
QS bisects PQR, mPQS = (5y – 1)°, and mPQR = (8y + 12)°. Find mPQS.
Protractor practice
Use a protractor to draw an angle with each of the following measures.
a) 33˚
b) 142˚
c) 90˚
d) 168˚