Question

A large chocolate bar has a base area of 47.1 square feet and it’s length is 0.7 feet longer than twice it’s width. Find the length and the width of the bar

Answer 1

The dimensions of the bar are width = 4.68099 feet and length = 10.06198 feet

Explanation:

A chocolate bar has a rectangular shape, therefore it's area is given by the following formula:

area = width*length

In this case the length is 0.7 feet longer than twice the width, therefore:

length = 2*width + 0.7

Applying the second equation on the first one and using the data from the question we have:

47.1 = width*(2*width + 0.7)

47.1 = 2*width² + 0.7*width

2*width² + 0.7*width = 47.1

width² + 0.35*width = 23.55

width =
`(-0.35 \pm √(0.35^2 -4*1*(-23.55)))/(2*1) = -0.175 \pm 4,85599`

width = 4.68099 or width = -5.03099

Since the width can't be negative, it can only be 4.68099 feet.

length = 2*4.68099 + 0.7 = 10.06198 feet.