Question

A woman plans to use one fourth of a 48 foot x 100 foot rectangular backyard to plant garden. Find the perimeter of the garden if the length is 40 feet greater than the width

Answer 1

Answer: 160ft.

Explanation:

First find the area of the 48ft x 100ft rectangular back yard.

Area of a rectangular = L x B

= 48 x 100

= 4800ft²

Now, find 1/4 of the rectangular backyard meant for garden

= 1/4 of 4800

= 1200ft²

Step 2:

To find the perimeter of the garden,first find the length and breath of the garden. From the dimension of the garden, the length is 40ft > width. In interpreting this,

We make the width of the garden to be. B = xft,

Therefore. L = (x + 40)ft

Now equate the product of this to 1200ft

x(x + 40) = 1200

Open the bracket

x² + 40x = 1200

x² + 40x - 1200 = 0

This is now a quadratic expression. Solving for x using any methods

x² + 60x - 20x - 1200 = 0

Solving by grouping

x(x + 60) - 20(x + 60) = 0

Collect common factors here

(x + 60)(x - 20) = 0

Therefore, x = -60 or 20

Remember, x cannot be negative, so x = 20ft. The width = 20ft, and the length = 60ft.

With this, we can determine the perimeter.

Formula for perimeter of a rectangular block

= 2( L + B )

= 2( 60 + 20 )

= 2(80)

= 2 x 80

= 160ft.