Question

A thin wire $20$ centimetres long is formed into a rectangle. If the width of this rectangle is $4$ centimetres, what is its length?

Answer 1

Perimeter of the wire $=20cm$

$2(l+w)=20$

$\Rightarrow 2[l+4]=20$

$\Rightarrow 2l+8=20$

$\Rightarrow 2l=12$

$\Rightarrow l=6cm$

Hence, length $=6cm$