1. If the surface area of a cylinder was covered in paper, and then the paper was cut apart and set flat on your desk, what shapes would you have in front of you? Today’s Plan: -Warm-up -Correct Homework -Cylinder Surface Area LT: I will calculate the surface area of prisms. 04/21/11 Surface Area

2. Correct Assignment Today’s Plan: -Warm-up -Surface Area LT: I will calculate the surface area of prisms. 04/21/11 Surface Area

3. If you could remove the lateral surface from a cylinder, like peeling a label from a can, you would see that it has the shape of a rectangle when flattened out. You can draw a net for a cylinder by drawing the circular bases (like the ends of a can) and the rectangular lateral surface as shown below. The length of the rectangle is the circumference, 2r, of the cylinder. So the area of the lateral surface is 2r. The area of each base is r 2. r Circumference of cylinder (2r) h Course 2 9-4 Surface Area of Prisms, Cylinders, and Spheres

4. SURFACE AREA OF A CYLINDER The surface area S of a cylinder is the sum of the areas of its bases, 2r 2, plus the area of its lateral surface, 2rh. S= 2r 2 + 2rh Course 2 9-4 Surface Area of Prisms, Cylinders, and Spheres

5. Find the surface area of the cylinder formed by the net to the nearest tenth. Use 3.14 for . Additional Example 2: Finding the Surface Area of a Cylinder 6 ft 8.3 ft S = 2r 2 + 2rh S  (2 · 3.14 · 6 2 ) + (2 · 3.14 · 6 · 8.3) Substitute. Use the formula. S  226.08 + 312.744 S  538.824 S  538.8 The surface area of the cylinder is about 538.8 ft 2. Multiply. Add. Round. Course 2 9-4 Surface Area of Prisms, Cylinders, and Spheres

6. Find the surface area of the cylinder formed by the net to the nearest tenth. Use 3.14 for . 9 ft 20 ft S = 2r 2 + 2rh S  (2 · 3.14 · 9 2 ) + (2 · 3.14 · 9 · 20) Substitute. Use the formula. S  508.68 + 1130.4 S  1,639.08 S  1,639.1 The surface area of the cylinder is about 1,639.1 ft 2. Multiply. Add. Round. Try This: Example 2 Course 2 9-4 Surface Area of Prisms, Cylinders, and Spheres

7. Lesson Quiz Find the surface area of each figure to the nearest tenth. 100.5 ft 2 352.0 ft 2 Insert Lesson Title Here 2,317.3 in 2 3. A drum is closed on the top and the bottom. The diameter of the drum is 18 in. The height is 32 in. Find the surface area. 1.2. Course 2 9-4 Surface Area of Prisms, Cylinders, and Spheres