Answer:
Step-by-step explanation:
First problem:
blank 2) on the left: PR = PQ + QR
blank 3) on the right: Replace PR in statement 1) with what we just completed in statement 2. Therefore:
2PQ = PR
2PQ = PQ + QR
blank 4) on the right: Subtract PQ from both sides, therefore
2PQ = PQ + QR
2PQ - PQ = PQ + QR - PQ
PQ = QR
