In the figure PQST is a parallelogram and TSR i... - JAMB Mathematics 1998 Question

In the figure, PQST is a parallelogram and TSR is a straight line. If the area of \(\bigtriangleup\)QRS is 20cm², find the area of the trapezium PQRT.

A_{(\bigtriangleup)} = (\frac{1}{2}) x 8 x h = 20

= (\frac{1}{2}) x 8 x h = 4h

h = (\frac{20}{4})

= 5cm

A_{(\bigtriangleup)}(PQTS) = L x H

A_{(\bigtriangleup)PQRT} = A_{(\bigtriangleup)QSR} + A_{(\bigtriangleup)PQTS}

20 + 50 = 70cm²

ALTERNATIVE METHOD

A_{(\bigtriangleup)PQRT} = (\frac{1}{2}) x 5 x 28

= 70cm²