Here, point R lies in the interior of PQ.

So, PR + QR = PQ

8+QR = 12

On subtracting 8 from both sides, we get

8 + QR-8 = 12-8 [by axiom 3]

QR=4 cm

Here, point R lies in the interior of PQ.

So, PR + QR = PQ

8+QR = 12

On subtracting 8 from both sides, we get

8 + QR-8 = 12-8 [by axiom 3]

QR=4 cm