The length of a rectangle is 4 more than the width. The area is 21 square inches. Find the dimensions.
A) The width is 3 inches, the length is 7 inches.
B) The width is 7 inches, the length is 3 inches.
C) The width is 2 inches, the length is 6 inches.
D) The width is 3 inches, the length is 10 inches.
E) The width is 6 inches, the length is 10 inches.

Question

Quizplus · Accepted Answer

Let x be the width of the rectangle. Then the length is x+4. We have the equation: x(x+4) = 21. This simplifies to x^2 + 4x - 21 = 0. Factoring this quadratic, we get (x+7)(x-3) = 0, so x=3 (since width cannot be negative). Therefore, the length is x+4 = 7. So the dimensions are 3 inches by 7 inches. Therefore, the correct answer is choice A.

The Length of a Rectangle Is 4 More Than the Width