Volume of Prisms OCR Stage 8

A Prism Cross section Volume of Prism = length x Cross-sectional area Cylinder Cuboid Cross section Triangular Prism Trapezoid Prism Volume of Prism = length x Cross-sectional area

Area Formulae r h b Area Circle = π x r2 Area Rectangle = Base x height h b h b Area Trapezium = ½ x (a + b) x h a b h Area Triangle = ½ x Base x height

Volume Cylinder Cross-sectional Area = π x r2 = π x 32 = 28.2743…..cm2 DO NOT ROUND! 3cm 5cm USE CALCULATOR ‘ANS’! Volume = length x CSA = 5 x 28.2743…. = 141.3716….cm3 = 141.4cm3

Volume Cuboid Cross-sectional Area = b x h = 7.2 x 5.3 = 38.16cm2 DO NOT ROUND! 7.2cm Volume = length x CSA USE ‘ANS’! = 10.6 x 38.16 = 404.496cm3 Sensible degree of accuracy = 404.5cm3

Volume Trapezoid Prism Cross-sectional Area = ½ x(a + b) x h = ½ x (6.3 + 1.7) x 4.9 1.7cm 8.2cm 6.3cm 4.9cm = 19.6cm2 DO NOT ROUND! Volume = length x CSA USE ‘ANS’! = 19.6 x 8.2 = 160.72cm3 Sensible degree of accuracy = 160.7cm3

Volume Triangular Prism Cross-sectional Area = ½ x b x h = ½ x 8.6 x 4.1 = 17.63cm2 4.1cm 4.9cm DO NOT ROUND! 6.2cm 8.6cm Volume = length x CSA USE ‘ANS’! = 17.63 x 6.2 = 109.306cm3 Sensible degree of accuracy = 109.3cm3