Work Step by Step
The perimeter of a rectangle is found by adding all the sides together. We can use the formula P=2(length)+2(width) to do so. Let w equal the width of the rectangle since we are given the perimeter and length of the rectangle. Plug in your given values into the equation, giving you: 84= 2(35) + 2w Multiply the 2 and the 35 on the right side of the equation to get: 84=70 + 2w Next, subtract 70 from both sides to get: 14=2w Lastly, divide both sides by 2 to get w by itself. 7=w This gives us our answer of 7 cm.