b) Construct a ∆PQR such that QR = 6.5 cm, ∠P = 60° and the altitude from P to QR is of length 4.5 cm.
Answer:
Construction:
- Draw a line segment QR = 5 cm.
- At Q, draw QE such that ∠RQE = 30°.
- At Q, draw QF such that ∠EQF = 90°.
- Draw the perpendicular bisector XY to QR, which intersects QF at O and QR at G.
- With O as centre and OQ as radius, draw a circle.
- The major arc QKR contains the angle 30°.
- From G, mark a point H on XY such that GH = 4.2 cm.
- Draw a line AB through H parallel to QR. This line intersects the circle at P and P'.
- Join QP and RP. Then ∆PQR is the required triangle.