The length of a rectangle is three times it's width. If the width is diminished by 1 m and length is increased by 3 m, the area of the rectangle that is formed is 72 m². Find the dimensions of the original rectangle.

the length is 15 m and the width is 5 m

Step-by-step explanation:

Let L represent the original length of the rectangle.

Let W represent the original width of the rectangle.

The length of a rectangle is three times it's width. This means that

L = 3W

If the width is diminished by 1 m and length is increased by 3 m, the area of the rectangle that is formed is 72 m². This means that

(L + 3)(W - 1) = 72

LW - L + 3W - 3 - 72 = 72 + 3

LW - L + 3W = 75 - - - - -- - - - - - 1

Substituting L = 3W into equation 1, it becomes

3W × W - 3W + 3W = 75

3W² = 75

W² = 75/3 = 25

W = √25 = ±5

The width cannot be negative. Therefore, the width is 5 m

L = 3W = 3 × 5 = 15 m