Find the perimeter of a rectangle with a length of 9 cm and a width of 4 cm less.

A rectangle is a rectangle whose opposite sides are equal. Their sum, that is, the perimeter, is calculated by the formula:

P = 2a + 2b.

According to the condition of the assignment, we find this value for such a figure if the length is 9 cm and the width is 4 cm less.

Let’s write the expression for the formula, substituting the known values:

P = 2 * 9 + 2 * (9 – 4).

First of all, we will find the value in parentheses, then we will perform multiplication, and only then addition:

P = 18 + 10 = 28 cm.