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Surface Areas of Pyramids and Cones. Section 6-3. Pyramid. A polyhedron in which one face (the base) can be any polygon. Lateral Faces are triangles that meet at a common vertex (vertex of pyramid) Named by the shape of the base. Pyramid.
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Surface Areas ofPyramids and Cones Section 6-3
Pyramid • A polyhedron in which one face (the base) can be any polygon. • Lateral Faces are triangles that meet at a common vertex (vertex of pyramid) • Named by the shape of the base
Pyramid • Altitude (Height)– the perpendicular segment from the vertex to the plane of the base • Slant Height – the altitude of a lateral face.
Pyramid Height Slant Height
Pyramid • Lateral Area – sum of the areas of the lateral faces (triangles) • ½ the product of the perimeter and slant height • Surface Area – sum of LA and the area of the base
Pyramid • LA = ½ pl • SA = LA + B
Cone Height Slant Height
Cone • LA = ½ · cl = ½ · 2πrl • LA = πrl • SA = LA + B • SA = πrl + πr2
Find LA and SA 20 cm 15cm