1. 12.5 Surface Areas of Pyramids What you’ll learn: 1.To find lateral areas of regular pyramids. 2.To find surface areas of regular pyramids.

2. Pyramids A pyramid is a polyhedron with all faces except for 1 intersecting at a vertex. The non-intersecting face is called the base. They are named by their base. Pyramids have the following characteristics: 1.The base is always a polygon 2.The altitude is the segment from the vertex that is perpendicular to the base. 3.Lateral faces intersect at the vertex and are always triangles.

3. Pyramids Parts vertex altitude lateral edge lateral face base slant height – the height of a lateral face. Regular Pyramid – a pyramid with a regular polygon as the base.

4. Formulas Lateral Area of a Regular Pyramid where P is the perimeter of the base and is the slant height. Surface Area of a Regular Pyramid where P is the perimeter of the base, is the slant height and B is the area of the base.

5. Find the surface area of the regular pyramid to the nearest tenth. 1.2. 8 m 6 m 8 m 4 m 12 cm15 cm

6. Homework p. 663 8-18 even, 29-32 all