Question

Construct a $\Delta$PQR with QR = 8, PQ= 6 PR = 4. Construct the incircle of the triangle and find the radius of the incircle.

• A. 4 cm
• B. 2.2 cm
• C. 4.2 cm
• D. 5.4 cm

Answer 1

The correct option is B

2.2 cm

1. Draw QR = 8 cm

2. With Q as a centre, draw an arc of radius 6 cm = PQ and with R as centre, draw one more arc of radius 4cm (=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 = 2.2 cm