the outside of the yard, indicated by the red arrow; It is measured in linear units such as feet or meters. ... Solution 2: P = 2(8 cm) + 2(3 cm) = 16 cm + 6 cm = 22 cm ... S = 18 cm ÷ 6 ... Find the perimeter of a triangle with sides measuring 10 inches, 14 inches and 15 inches.