9-5 Surface Area of Space Figures
9-5 Surface Area of Space Figures
9-5 Surface Area of Space Figures
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Integrated I<br />
Section 9-5 <strong>Surface</strong> <strong>Area</strong> <strong>of</strong> <strong>Space</strong> <strong>Figures</strong><br />
<strong>Surface</strong> <strong>Area</strong> <strong>of</strong> a Cylinder<br />
Cylinder: A space figure with a curved surface and 2 congruent, parallel bases<br />
that are circles.<br />
base<br />
<strong>Surface</strong> <strong>Area</strong> <strong>of</strong> a Cylinder = area <strong>of</strong> two circular bases + area <strong>of</strong> curved<br />
surface<br />
S.A. = 2πr² + 2πrh<br />
Example 3<br />
Tennis balls are packaged in a cylindrical can 8 inches high with a diameter <strong>of</strong> 3<br />
inches. How much material is needed to make the cylinder?<br />
Solution<br />
S.A. = 2πr² + 2πrh<br />
= 2π(1.5)² + 2π(1.5)(8)<br />
= 14.1 + 75.4<br />
= 89.5 in 2<br />
Example 4<br />
Find the surface area.<br />
Solution<br />
Find the surface area <strong>of</strong> a cylinder then divide by 2!<br />
Don’t forget to also include the bottom!!!<br />
S.A. = 2πr² + 2πrh<br />
= 2π(2)² + 2π(2)(12)<br />
= 25.1 + 150.7<br />
= 175.8 in 2<br />
SA <strong>of</strong> ½ <strong>of</strong> the cylinder = 175.8/2 = 87.9 in 2<br />
SA <strong>of</strong> the bottom (rectangle) = 4(12) = 48 in 2<br />
Total SA = 87.9 + 48 = 135.9 in 2<br />
9-5 <strong>Surface</strong> <strong>Area</strong> <strong>of</strong> <strong>Space</strong> <strong>Figures</strong>
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