Final answer:
The length and width of the rectangle can be determined by setting up the equation for perimeter (P = 2L + 2W), substituting the given values, and solving for L and W. The length (L) is 21 cm, and width (W) is 15 cm.
Step-by-step explanation:
The student is asked to find the length and width of a rectangle given that the width is 6cm less than the length and the perimeter is 72 cm. To solve this:
- Let the length be L cm, so the width will be L - 6 cm.
- Write the equation for the perimeter: P = 2L + 2W, where P is the perimeter, L is the length, and W is the width.
- Substitute the expressions for L and W and the given perimeter into the equation: 72 = 2(L) + 2(L - 6).
- Simplify and solve the equation for L: 72 = 2L + 2L - 12, which simplifies to 72 = 4L - 12, and then 4L = 84, so L = 21 cm.
- Calculate W by subtracting 6 from L: W = L - 6, so W = 21 - 6, which means W = 15 cm.
The dimensions of the rectangle are 21 cm for the length and 15 cm for the width.