1. Section 12.3 Surface Area of Pyramids and Cones

2. Pyramid: polyhedron with one base lateral faces- triangles Slant Height: altitude of any lateral face Base height slant height

3. To find the slant height of the pyramid, use the PYTHAGOREAN THEOREM Ex. 1 Slant Height 321 L -slant height ½ side length 150 a² + b² = c² ( l² )

4. Surface Area of a Regular Pyramid: S = B + ½ P l B- area of the base P- perimeter of the base L - slant height

5. Ex. 3 a² + b² = l ² 12² + 4² = l ² 12.65 = l 12.65 S = B + ½ P l S = (8  8) + ½ (32)(12.65) S = 64 + 202.4 S = 266.4 ft²

6. Surface Area of a Right Cone: S = πr² + πr l L - slant height r- radius

7. To find the slant height of a cone, use the PYTHAGOREAN THEOREM Ex. 7 a² + b² = l ² 14² + 8² = l ² 16.1 = l 16.1 S = πr² + πr l S= π (8²) + π (8) (16.1) S = 201.06 + 404.64 S = 605.7 m²