Question

What are the remaining angle measures if the figure is to be a parallelogram?

Answer 1

We conclude that:

m∠B = 101°

m∠C = 79°

m∠D = 101°

Explanation:

Given the parallelogram ABCD

We know that a parallelogram has opposite angles that are congruent.

Here,

The angles ∠A and ∠C are opposite angles.

Thus,

• ∠A = ∠C

The angles ∠B and ∠D are opposite angles.

Thus,

• ∠B = ∠D

Determining the measure of angles of a parallelogram:

As

∠A = 79°

We know

• ∠A = ∠C

Thus, the measure of the angle ∠C is:

m∠C = 79°

We know that the sum of the measure of two consecutive angles is 180°.

As ∠A and ∠D are consecutive angles, so

∠A + ∠D = 180°

substituting ∠A = 79° in the equation

79° + ∠D = 180°

subtracting 79° from both sides

79° + ∠D - 79° = 180° - 79°

∠D = 101°

Thus, the measure of the angle D is:

m∠D = 101°

We know that the angles ∠B and ∠D are opposite angles.

Thus,

• ∠B = ∠D

so if m∠D = 101° then ∠B is also 101°.

Therefore, the measure of angle B is:

m∠B = 101°

Hence, we conclude that:

m∠B = 101°

m∠C = 79°

m∠D = 101°