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### Surface Area of Pyramids and Cones

• Pyramids
• The vertex is the point where all the faces except the base intersect
• The base is the polygon that connects all the lateral faces
• Lateral faces always form triangles
• Lateral edges have the vertex as an endpoint
• The altitude is the segment from the vertex perpendicular to the base
• Regular pyramid
• The base is a regular polygon
• The endpoints of the altitude is the vertex and the center of the base
• All the lateral faces are congruent isosceles triangles
• The slant height is the height of each lateral face
• Lateral area of a regular pyramid = ½(perimeter of base × slant height)
• Surface area of a regular pyramid = lateral area + area of the base
• Cone
• The base is a circle
• The axis is the segment whose endpoints are the vertex and the center of the base
• The altitude is the perpendicular height
• Lateral area of a right cone = π × radius × slant height
• Surface area of a right cone = lateral area + area of the circle

## Surface Area of Pyramids and Cones

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