The length of a retangle is fixed at 21 cm. What widths will make the perimeter greater than 76 cm?

2(21) + 2w > 76

solve for w

To determine the widths that will make the perimeter of the rectangle greater than 76 cm, we first need to understand the formula for the perimeter of a rectangle.

The perimeter of a rectangle is given by the formula:

Perimeter = 2 * (Length + Width)

In this case, the length of the rectangle is fixed at 21 cm. Let's denote the width of the rectangle as 'w'.

Now, we can substitute the values into the formula to obtain the equation:

76 < 2 * (21 + w)

To solve this inequality, let's simplify it step-by-step:

76 < 2 * (21 + w)
76 < 42 + 2w
76 - 42 < 2w
34 < 2w
34/2 < w
17 < w

Therefore, any width greater than 17 cm will make the perimeter of the rectangle greater than 76 cm.