Multiple choice What is the maximum area of a rectangle, the perimeter of which is 18 cm? $20.25 cm2$ $20.00 cm2$ $19.75 cm2$ $19.60 cm2$ Reveal answer Fill a bubble to check yourself A Correct answer Explanation For a fixed perimeter, a rectangle achieves maximum area when it is a square. With perimeter 18 cm, each side of the square is 18/4 = 4.5 cm, giving area 4.5 × 4.5 = 20.25 cm².