Question

Compute the area of trapezium PQRS in Fig. 15.76.

Answer 1

Given:

• QR = 17 cm

• QT = PT = SR = 8 cm

To find out:

Find the area of trapezium.

Solution:

In △QRT

QR² = QT² + RT² [ By pythagoras therome]

➞ (17)²= (8)² + RT²

➞ 289 = 64 + RT²

➞ RT² = 289 - 64

➞ RT² = 225

➞RT = √225

➞RT = 25 cm

Now,

Area of trap. = (Area of RSPT ) + ( Area of △QRT)

= ( PT × RT ) + (1/2 × TQ × RT )

= ( 8 × 15 ) + ( 1/2 × 8 × 15 )

= 120 + ( 4 × 15)

= 120 + 60

= 180 cm²

Answer 2

Given:

• QR = 17cm

• QT = PT = SR = 8cm

Find the area of trapezium.

Solutions:

In ∆QRT

QR² = QT² + RT² [ By Pythagoras theorem]

(17)² = (8)² + RT²

289 = 64 + RT²

RT² = 289 - 64

RT² = 225

RT = 15

Now, Area of trap. = (Area of RSPT) + (Area of ∆ QRT)

(PT × RT) + (1/2 × TQ × RT)

(8 × 15) + (1/2 × 8 × 15)

120 + (4 × 15)

120 + 60

180cm²

silentlover45.❤️