To find the perimeter of a rectangle, we can use this formula: 
Where L is the length and W is the width.
We know the perimeter and we know the length and we want to find the width.
Substitute the values back into the formula.
2(35) + 2W = 84
70 + 2W = 84
2W = 14 <-- Subtract both sides by 70
W = 7 <-- Divide both sides by 2
So, width is 7 meters long.
Where L is the length and W is the width.
We know the perimeter and we know the length and we want to find the width.
Substitute the values back into the formula.
2(35) + 2W = 84
70 + 2W = 84
2W = 14 <-- Subtract both sides by 70
W = 7 <-- Divide both sides by 2
So, width is 7 meters long.