Question

ABCD is a parallelogram. The perimeter is $144$ cm and BC $=20$ cm then find AB.

Answer 1

We are given thta $ABCD$ is a parallelogram

i.e, $AB=CD$ & $AD=BC$

so, the perimeter will be

$AB+BC+CD+DA=144$

$AB+BC+AB+BC=144$

$\therefore 2(AB+BC)=144$

$\therefore AB+BC=72$

$\therefore AB=72-BC$

$\therefore AB=72-20$

$\therefore AB=52cm$