Answer:
Proof with statement is below.
Step-by-step explanation:
To Prove:
m∠RPQ + m∠PRQ + m∠PQR = 180°
Proof:
Draw line ZY parallel to segment PQ ............{Construction}
1. m∠ZRP + m∠PRQ + m∠QRY = m∠ZRY .....{Angle Addition Postulate}
2. ∠ZRP ≅ ∠RPQ ........{Alternate angles equal as ZY || PQ}
3. ∠QRY ≅ ∠PQR .........{Alternate angles equal as ZY || PQ}
4. m∠RPQ + m∠PRQ + m∠PQR = m∠ZRY ....{The three angles of ΔPQR equal 180° according to Substitution }
5. m∠ZRY = 180° ......{Definition of a Straight Angle}
6. m∠RPQ + m∠PRQ + m∠PQR = 180° ...{Additive Property of Equality}...............PROVED