#### Answer

7 cm

#### Work Step by Step

Perimeter = 2 times the length + 2 times the width
We know the perimeter and the length, but not the width.
Let w stand for width.
2(35) + 2(w) = 84
70 + 2w = 84
- Subtract and move 70 to the right side of the equation.
2w = 14
- Divide both sides by 2.
w = 7
The width of the fence is 7 cm.