5.2 Angle Bisectors and Perpendicular Lines

Angle Bisectors• To bisect something is to

cut it into two equal parts• The ray that divides the

angle is called an angle bisector

• Measure angle ACB. What degree is it?

• Measure angle ACD. What degree is this?

• Measure angle DCB. What is this degree?

• Does the line D bisect angle ACB?

• If I bisect a right angle, what will the size of each angle be?

• Bisect the following angles.

• An angle is bisected. Each resulting angle is 780. How big was the original angle?

• The size of one resulting angle after the original angle is bisected is equal to the supplement of the original angle. What is the measure of the original angle?

• Using a protractor determine which of the following lines are perpendicular.

• A crooked table leg makes an angle of 86.70 with the tabletop. How much must the carpenter move the leg so that it is perpendicular to the tabletop?

• At what approximate angle does the hill incline from the horizontal?

• A carpenter is inlaying different types of wood on a tabletop. What must be the size of angles a, b, c, and d? ((hint: remember that a straight line is how many degrees? And the 3 angles of a triangle always add to 180 degrees)

• Practice questions page 229# 2, 4 and worksheet