Question

Compute the area of trapezium PQRS in figure.

Answer 1

From figure, Area of trapezium PQRS = Area of rectangle PSRT + Area of ΔQRT 

= PT × RT + 1/2 (QT×RT) 

= 8 × RT + 1/2(8 × RT) 

= 12 RT 

In right ΔQRT, 

Using Pythagorean Theorem, 

QR² = QT² + RT² 

RT² = QR² − QT² 

RT² = 172 − 82 = 225 

or RT = 15 

Therefore, Area of trapezium = 12 x 15 cm² 

= 180 cm²