Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website. 234 Section 5 Volume, Weight, and Bending Metal C = π × D π = 3.14 D – thickness = 14″ – 3/8″ = 13 5/8″ = 13.625″ C = 3.14 × 13.625″ = 42.7825″ C = 42 12/16″ (rounded) C = 42 3/4″ Flat-out length is 42 3/4″. Inside Diameter To determine fl at-out length when you are given the inside diameter, calculate the circumference using the inside diameter plus the metal thickness. C = π × D D + thickness = 600 mm + 10 mm = 610 mm C = 3.14 × 610 mm = 1915 mm (rounded) C = 1915 mm Flat-out length is 1915 mm. 14″ Thickness ⅜″ 600 mm Thickness 10 mm Goodheart-Willcox Publisher Goodheart-Willcox Publisher