Chapter 15 Area Set 15.4
∴ The area of the triangle is 756 sq.cm.
Question 2.
Look at the measures shown in the given figure and find the area of ☐PQRS.
= 270 sq.m
In ∆PSR, m∠PSR = 90°
[l(PR)]² = [l(PS)]² + [l(SR)]²
…[Pythagoras theorem]
= (36)² + (15)²
= 1296 + 225
∴ l(PR)² = 1521
∴ l(PR) = 39m
…[Taking square root of both sides]
In ∆PQR, a = 56m, b = 25m, c = 39m
A(☐PQRS) = A(∆PSR) + A(∆PQR)
= 270 + 420
= 690 sq. m
∴ The area of ☐PQRS is 690 sq.m
Question 3.
Some measures are given in the figure, find the area of ☐ABCD.
∴ The area of ☐ABCD is 570 sq.m.