Example 1 - Chapter 11 Class 9 Constructions

Example 1

Construct a triangle ABC, in which ∠B = 60°, ∠C = 45° and AB + BC + CA = 11 cm

Steps of Construction:

1. 1.Draw a line segment PQ equal to AB  + BC + CA = 11 cm.
2. Make ∠ LPQ = ∠B = 60° and ∠ MQP= ∠C = 45°
3. Bisect ∠ LPQ and ∠ MQP. Let these bisectors intersect at a point A .
4. Draw perpendicular bisectors of line AP and AQ
5. Let XY intersect PQ at B and RS intersect PQ at C.
6. Join AB and AC

Thus, Δ ABC is a the required triangle