Question

Construct $\Delta$PQR with QR = 6.5 cm, PQ= 5.5 cm, PR = 5 cm. Construct and find the radius of incircle of the $\Delta$PQR

• A. 4.6 cm
• B. 1.6 cm
• C. 2.8 cm
• D. 3.2 cm

Answer 1

The correct option is B

1.6 cm

1. Draw QR = 6.5 cm

2. With Q as a centre, draw an arc of radius 5.5 cm = PQ and with R as centre, draw one more arc of radius 5cm (=PR). Let these arc intersects each other at point P.

3. Draw bisectors of PQR and PRQ, which meet each other at point O.

4. Through point O, draw OP $\perp$ BC.

5. With O as centre and OA as radius, draw the required incircle which will touch all the three sides of triangles.

6. Measure OA, the radius of the incircle

7. Radius of incircle = 1.6 cm