Question

A triangle does not have a radius we need to replace it.

ABCD is a trapezium in which AD||BC, AD = 8 cm, BC = 18 cm and the area of $\Delta DEC=30c{m}^2$. If AB||DE, then area of trapezium ABCD is ___ $c{m}^2$

• A. 64
• B. 70
• C. 78
• D. 84

Answer 1

The correct option is C

78

(Opposite sides of parallelogram)

BE = 8 cm

EC = BC - BF

= 18 - 8

= 10 cm

Area of $\Delta DEC=\frac{1}{2}\times EC\times h$

$30=\frac{1}{2}\times 10\times h$

$h=6cm$

Area of trapezium $=\frac{1}{2}(AD+BC)\times h$

$=\frac{1}{2}(8+18)\times 6$

Hence (C)