# The length of a  rectangle  is twice its width. If the  perimeter  of the rectangle is  30 cm,  find its  area .?

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• Abbreviations: Length = L, Perimeter = P, Width = W, Area = A

Area = Length:Width = L:W = 2:1 • L:W = 2:1

2 + 1 = 3 parts

30/3 = 10 = 1 part

10 x 2 = 20 = 2 parts

However, this is 2L and 2W

therefore L = 20/2 = 10

and W = 10/2 = 5

Arera = L x W

= 10 x 5

= 50 sq cm

• L = 2W

P = 30 = 2(L+W) = 2(3*W) = 6W

So W = 5 cm and L = 10 cm

A = L*W = 10*5 = 50 cm^2

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• 50 sq cm is its  area

• The length of a rectangle is twice its width.

If the perimeter of the rectangle is 30 cm,

its area is 50 cm^2.

• Area of rectangle: 10 times 5 = 50 square cm

• l = 2w

p = 2l + 2w

30 = 2l + 2w

Substitute for l = 2w

30 = 2(2w) + 2w

30 = 4w + 2w

30 = 6w

Divide both sides by 6

5 = w

w = 5 cm

Remember

l = 2w

l = 2(5)

l = 10 cm

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Area

a = l * w

a = 10 * 5

a = 50 cm² <––––––

• it is 5 x 10 ... you do the rest.  ps -- on the exam you'll have to show how you proved that

• The length is 10 cm and the width is 5 cm

The area is 5 cm x 10 cm = 50 cm