Example-1 :- Construct a triangle ABC, in which ∠B = 60°, ∠ C = 45° and AB + BC + CA = 11 cm.
Solution :-Steps of Construction : 1. Draw a line segment PQ = 11 cm.( = AB + BC + CA). 2. At P construct an angle of 60° and at Q, an angle of 45°.3. Bisect these angles. Let the bisectors of these angles intersect at a point A. 4. Draw perpendicular bisectors DE of AP to intersect PQ at B and FG of AQ to intersect PQ at C. 5. Join AB and AC (see Fig.). Then, ABC is the required triangle.