Question

16. What is the measure of ZAOB?

Answer 1

Find angle a2 which is 40 degrees because it is parallel to angle c.

Find the total of d1 and d2.
total of d1 and d2: 180 - 40 - 40 = 100 degrees

Find d1 and d2 separately.
100 divided by 2 = 50 degrees

Use d1 to find b1 to find total of a1 and a2.

b1 is parallel to d1 so b1 = 50 degrees

a1 and a2 = 180 - 50 - 50 = 80 degrees

a1 = 80 divided by 2 = 40

Since a1 and c1 are parallel due to alternate angles, c1 is 40 degrees

Find b2 now which requires you to do total - minus all angles in the triangle with angle b2.

180 - 40 - 50 - 40 = 50 degrees (angle b2)

AOB has b1 and a1.

40 + 50 = 90 degrees (a1 + b1 = AOB)

The answer is 90 degrees