Question

Given: BDis a diameter

m 1 = 100°
m BC= 30°

m2 =

30
80
100

Answer 1

∠2 = 80°

Explanation:

Since BD is a diameter then

∠1 + ∠2 = 180°, that is

100° + ∠2 = 180° ( subtract 100° from both sides )

∠2 = 180° - 100° = 80°

Answer 2

B. 80

Explanation:

We have been given a circle. We are asked to find the measure of angle 2.

Since BD is diameter of our given circle, so angle 1 and angle 2 will be linear pair of angles.

We know that linear angles add up-to 180 degrees, so we can set an equation as:

`m\angle 1+m\angle 2=180^(\circ)`

`100^(\circ)+m\angle 2=180^(\circ)`

`100^(\circ)-100^(\circ)+m\angle 2=180^(\circ)-100^(\circ)`

`m\angle 2=80^(\circ)`

Therefore, measure of angle 2 is 80 degrees and option B is the correct choice.