Surface Area of a Prisms Remember Prisms are

Surface Area of a Prisms Remember: Prisms are 3 dimensional shapes that have a constant cross-sectional area. Cuboid Triangular-based prism Rectangular-based prism Pentagonal-based prism Cylinder Hexagonal-based prism Octagonal-based prism Circular-based prism

Diagrams Not to scale Surface area of prisms. To find the surface area of a prism, find the area of all the faces and add them together 1 Surface area = 2 x 3 x 10 + 2 x 4 x 3 + 2 x 4 x 10 3 cm = 60 + 24 + 80 4 cm = 164 cm 2 10 cm 2 2 x 8 x 14 = 224 (top and bottom) 5 cm 2 x 8 x 7 = 112 (L and R side views) 2 cm 14 cm 8 cm 2 x 14 x 2 = 56 2 x 5 x 2 = 20 Surface area = 412 cm 2

Diagrams Not to scale Find the surface area of the following prisms. 3 4 4 m 2. 5 m 3 mm 2. 5 mm 3 m 2 mm 4 mm 6 m 2 x 6 x 3 = 36 (top and bottom) 3 x rectangles give: 2 x 4 x 3 = 24 (L and R sides) 5 x 2 + 4 x 2 + 3 x 2 = 24 2 x 6 x 2. 5 = 30 2 x 2. 5 x 1. 5 = 7. 5 2 x triangles give: Surface area = 97. 5 cm 2 ½ (4 x 3) x 2 = 12 Surface area = 36 mm 2

Diagrams Not to scale Now try these. 5 2 x 10 x 5 = 100 (T and B) 6’’ 3’’ 2 x 6 x 5 = 60 (L and R) Front and back gives: 2 x (10 x 6 - 2 x 3) = 108 5’’ 2 x 5 x 3 = 30 10’’ Surface area = 298 inches 2 6 3 x rectangles give: 13 x 2 + 12 x 2 + 5 x 2 = 60 5 ft 2 x triangles give: 13 ft ½ (12 x 5) x 2 = 60 2 ft 12 ft Surface area = 120 ft 2