Santhosh K. The sides of a rectangle are in the ratio 4 : 5 and its perimeter is 90 cm.Find the dimensions of the rectangle and hence its area. 1 Expert Answer Beth R. answered • 03/18/16 Biology & Chemistry Degrees w/ Teaching & Tutoring Experience
We know that the sum of the lengths of all sides of your rectangle are equal to 90 and that the sides have a ratio of 4:5. We can solve this using simple algebra. Lets say the shorter side is 4x in length and the longer side is 5x based on the ratio given in the problem. For all rectangles, perimeter=2(length)+2(width) So if we substitute the x values we assigned above, we get 2(4x)+2(5x)=90 We can simplify this equation: Then divide both sides by 18 to solve for x; If shorter side = 4x, and x =5, the width is 4*5 = 20cm If longer side = 5x and x=5, the length is 5*5 = 25cm For all rectangles, Area=length x width Using the values we calculated above: Area = 20cm x 25cm = 500cm |