The length of a rectangle is five times the width. The area of the rectangle is 1620 cm(squared) Work out the width of the rectangle.
If the length is 5 times the width we can say that length=5a if width=a. We know the equation for: the area of a rectangle= length x width.In this case: area= 5a x a= 5a2 and from the question we know that is equal to 1620. The rest is algebra what you do to one side you must also do to the other side of the equality sign, using this you can get a by itself. 5a2 = 1620 (divide by 5) a2 = 324 (square root) a = (plus or minus) 18 in this case we can ignore -18 because a length can't be negative. so the width is 18cm.(side note the length is 5 x 18 = 90cm.)
