Assume that the length of the rectangle is l and the width is w. From the givens, we can conclude that: l=9+w Area of rectangle=l * w 90 = (l *w) = (9+w)(w) 90=9w+w^2 w^2+9w-90 = 0 either w=6 or w=-15 (this value is rejected as length cannot be negative)
therefore, the dimentions are as follows: length=9+6=15 cm width=6 cm