A cuboid with a volume of 912cm^3 has the dimensions 4 cm, (x + 2) cm and (x + 9) cm. Find an equation in terms of x and solve to find the dimension.
912 = 4(x+2)(x+9)228 = (x+2)(x+9)228 = x2 + 11x + 180 = x2 + 11x -210using the quadratic formula we obtain x = -10 or x = 21As dimensions must be positive; x must equal 21Hence; the dimensions are 4, (21+2), (21+9) which implies dimensions of 4cmx23cmx30cm
