Question

the width of a rectangle is 5cm and its diagonal is 13 cm what is its perimeter

Answer 1

By pythagoras theorem,
${13 }^{2} = {5}^{2} + {l}^{2}$
${l}^{2} = 169 - 25$
$l = \sqrt{144}$
l=12
b=5
perimeter= 5+5+12+12
=34cm

Answer 2

Diagonal can be found out using Pythagoras theorem .

Length = l

Width = 5 cm

Diagonal = 13 cm

= l²+5² = 13²

= l²+25 = 169

= l² = 169-25

= l² = 144

Therefore, l = 12 cm

Perimeter = 2(l+b)

= 2(12+5) ⇒2(17)

Perimeter= 34 cm