Geometry Angle Bisector

Angle Bisectors

Angle Bisector

Example

Bisecting an angle means dividing it into two congruent angles.

Fill in the Blanks

An angle is bisected, forming two new angles. Each new angle has a measure of 15°. What was the measure of the original angle? (enter number only)

Solution:

Each new angle measures 15°. Multiply by 2 to find the original, larger angle.

15° × 2 = 30°

So, the original angle measured 30°.

Fill in the Blanks

After bisecting an angle, Eric has two new angles, each with a measure of 19°. What was the measure of the original angle? (number only)

Fill in the Blanks

After bisecting an angle, Patty has two new angles, each with a measure of 12°. What was the measure of the original angle?

Multiple Choice

The figure shows a triangle with one of its angle bisectors. Find x if m∠2 = 4x + 5 and m∠1 = 5x − 2.

• x = 7

• x = 3

• x = -7

• x = 1/3

Multiple Choice

Find x:

• 5

• 3

• 9

• 8

Fill in the Blanks

Given the segment BP bisects ∠CBD Find m∠2 if m∠2 = 7x + 5 and m∠1 = 9x − 5.

FIND m∠2=