Compute the area of trapezium PQRS in Fig. 15.76.
We have,
Area of trapezium PQRS = Area of rectangle PSRT + Area (Δ QRT)
Area of trapezium PQRS = PT * RT + (QT * RT)
= 8 * RT + (8 * RT)
= 12 * RT
In Δ QRT, we have
QR2 = QT2 + RT2
RT2 = QR2 - QT2
RT2 = (17)2 - (8)2
= 225
= 15
Hence,
Area of trapezium PQRS = 12 * 15
= 180 cm2