best answer get brainlest In parallelogram ABCD, the measure of angle A is 99°. What are the measures of the other 3 angles? Explain how you know.

Step-by-step explanation:

Let us revise the properties of a parallelogram

In any parallelogram:

Every two opposite sides are parallel

Every two opposite sides are equal in length

Every two opposite angles are equal in measure

Every to adjacent angles are interior supplementary angles

Let us solve our question

In parallelogram ABCD

∵ AD and BC are opposite sides

∴ AD // BC

∵ ∠A and ∠B are adjacent angles

→ That means ∠A and ∠B are interior supplementary angles

∴ ∠A and ∠B are supplementary angles

∵ The sum of the measures of the supplementary angles is 180°

∴ m∠A + m∠B = 180°

∵ m∠A = 99°

∴ 99° + m∠B = 180°

→ Subtract 99° from both sides

∴ 99° - 99° + m∠B = 180° - 99°

∴ m∠B = 81°

B:81

C:99

D:81

Step-by-step explanation:

In a parallelogram, opposite angles are congruent and consecutive angles (angles next to each other) are supplementary, or add to 180. Considering that there is no diagram, we can use our imagination here. So B is next to A, so <A+<B=180. <B must equal 81. I repeated this process for the rest of the angle measures.

13

step-by-step explanation:

169-1=168

168-3=165

165-5=160

160-7=153

153-9=144

144-11=133

133-13=120

120-15=105

105-17=88

88-19=69

69-21=48

48-23=25

25-25=0

since it took 13times to completely subtract it hence its square root is 13