Answer:
The proof is explained step-wise below :
Step-by-step explanation:
Given : ∠C and ∠R are supplementary. Also, ∠C and ∠R are congruent
To Prove : ∠C and ∠R are right angles ⇒ ∠C = ∠R = 90°
Proof : Given ∠C and ∠R are congruent and the congruent angles are equal in measure.
⇒ m∠C = m∠R .........(1)
Now, ∠C and ∠R are supplementary
⇒ ∠C + ∠R = 180°
⇒ ∠C + ∠C = 180° ( From equation (1) )
⇒ 2∠C = 180°
⇒ ∠C = 90°
Hence, ∠C = ∠R = 90°
⇒ ∠C and ∠R both are right angles.
Hence Proved.