Question

ABCD is a parallelogram whose height DE is 4 cm and base AB is 10 cm. If the height AF on BC is 5 cm, find the width BC ?

Answer 1

Area of a parallelogram
=base $\times$ altitude
Area =$10\times 4=40c{m}^2$
when BC is the base
Area =$BC\times AF$
$40=BC\times 5BC=\frac{40}{5}=8cm$