Respuesta :

Step-by-step explanation:

Let;

perimeter = 420cm

L = length

w = width

perimeter of rectangle = 2l +2w

420= 2l + 2w

but;

width = L - 30cm ( 30 cm less than length)

420cm = 2L + 2( L - 30cm)

420cm = 2L + 2L -60cm

420cm + 60cm = 2L + 2 L

480 Cm = 4L

L = 480cm ÷ 4

L = 120 cm

therefore, the length is 120 cm and width,

(L - 30cm)

= 120cm - 30cm

= 90cm

Therefore the width is also 90cm