Answer:
- 160°, 20° and 160°
Step-by-step explanation:
Let us assume A, B, C and D are the four angles of the parallelogram. Where, ∠A = 20° and we have to find the measure of ∠B, ∠C and ∠D
So, If ∠A = 20°, then So, also ∠C = 20°.
- <em>[Opposite angles of a parallelogram are equal to each other]</em>
Therefore,
- The measure of ∠C is 20°
⠀
And, ∠A and ∠B are adjacent angles. We know,
- Sum of two adjacent angles = 180°
So,
⇒ ∠A + ∠B = 180°
⇒ 20° + ∠B = 180°
⇒ ∠B = 180° – 20°
⇒ ∠B = 160°
So,
- The measure of ∠B = 160°
⠀
So, If ∠B = 160°, then So, also ∠D = 160°.
- <em>[Opposite angles of a parallelogram are equal to each other]</em>
Therefore,
- The measure of ∠D is 160°
