Geometry 11-3

Surface Areas of Pyramidsand Cones

• Pyramid- Polyhedron with one base and triangles that meet at a common vertex

• Regular Pyramid- The base is a regular polygon

• Height- the altitude of the pyramid• Slant Length, or Slant Height- the height of the

triangles that are on the pyramid

Lateral Area

𝐿𝐴=12𝑝𝑙

𝐿𝐴=12𝑝𝑙

320𝑚2

Surface Area

𝑆𝐴=12𝑝𝑙+𝐵

• You have a pyramid with a pentagon base. The base of each triangle is 7 inches. The altitude of the pyramid is 10 inches. What if the surface area?

Lateral Area

𝐿𝐴=𝜋𝑟𝑙

264.58𝜋𝑐𝑚2

Surface Area

𝑆𝐴=𝜋𝑟𝑙+𝜋𝑟 2

91.32𝜋𝑚2

iRAT

• Lateral Area of a square base pyramid with base sides of 8 feet and a slant height of 5 feet.

• Surface Area of a cone with a radius of 12 cm and a height of 5 cm.

Homework

Page 620 #1-13, 30