What is the length of the side of the square that has the same area as a rectangle that has a length of 27 mm and a width of 15 mm? Round to the nearest tenth, if needed.
Area of rectangle = 15 * 27 = 405 mm^2
Area of square = side^2 .......so...
405 = side^2 take the square root of both sides
√405 = side ≈ 20.1 mm