A rectangle has a length of 15 cm and an area of 159 cm². If the area is increased to 1⅓ times the original by extending only the length, what is the new perimeter of the rectangle?

Explanation

The original area is 159 cm² with length 15 cm, so the width is 159 ÷ 15 = 10.6 cm. The new area is 1⅓ times 159, which is 212 cm². Since only the length changes, new length = 212 ÷ 10.6 = 20 cm. The perimeter is 2 × (length + width) = 2 × (20 + 10.6) = 61.2 cm, rounded to 60 cm.