Steps of construction :
1. Draw a line segment AB = 6 cm.
2. Make an angle PAB = 60˚
3. Draw the perpendicular bisectors LM of AB.
4. Draw TA ⊥ AP at A.
5. Let LM and TA intersect at O.
6. Draw the circle with centre O and radius OA. Then any angle in the major segment, ∠PAB = 60˚ (Angle in alternate segment).
7. Let LM intersect AB at N, then N is the mid-point of AB. Taking N as centre and 4 cm radius, draw arcs intersecting the circle C, C’.
8.Join CA, CB and C’A and C’B. Then the required triangle is ABC or ABC’.