Chapter 11.2 Surface Areas of Prisms and Cylinders
Vocabulary Prism = a polyhedron with exactly two congruent, parallel faces, called bases. Other faces are lateral faces. You name a prism by the shape of its bases
Examples: Right prisms Oblique Prisms
Vocabulary Altitude = perpendicular segment that joins the planes of the bases Height = the length of altitude
Vocabulary Lateral area = the sum of the areas of the lateral faces Surface area = sum of the lateral area and the area of the two bases
Theorem 11.1 lateral and Surface Areas of a Prism The lateral area of a right prism is the product of the perimeter of the base and the height P = perimeter of base H= height
Theorem 11.1 lateral and Surface Areas of a Prism The surface area of a right prism is the sum of the lateral area and the areas of the two bases B= area of base
Example #1 Find the lateral area and total surface area of the prism
Theorem 11.2 lateral and Surface Areas of a Cylinder The lateral area of a right cylinder is the product of the circumference of the base and the height of the cylinder
Theorem 11.2 lateral and Surface Areas of a Cylinder The surface area of a right cylinder is the sum of the lateral area and the areas of the two bases
Example #1 Find the lateral surface area of a cylinder with a base radius of 3 inches and a height of 9 inches. L. S. A. = 2π(3)(9) = 54π inches 2
Example #2 Find the total surface area of a cylinder with a base radius of 5 inches and a height of 7 inches T. S. A. = 2π(5)(7) + 2π(5) 2 = 70π + 50π = 120π inches 2
Important You need to know the concept of lateral face and surface area. For the right prisms, you know that the lateral surface is a rectangle, you know the area of the rectangle and you can then multiply by however many there are.
Classwork/Homework Pgs #1-16, 34