Question

Construct $∆$ PQR, in which $\angle$Q = ${70}^{°}$, $\angle$R = ${80}^{°}$ and PQ + QR + PR = 9.5 cm.

Answer 1

Steps of construction:

(1) Draw seg AB of 9.5 cm length.
(2) Draw a ray making angle of 35° at point A.
(3) Draw another ray making an angle of 40° at point B.
(4) Name the point of intersection of the two rays as P.
(5) Draw the perpendicular bisector of seg AP and seg BP.
Name the points as Q and R respectively where the perpendicular bisectors intersect line AB.
(6) Draw seg PQ and seg PR.

Therefore, △PQR is the required triangle.