1. 5
Rational Numbers: Positive and Negative Decimals

2. R.1 Fractions
5.10 Geometry Applications: Circles, Cylinders, and Surface Area
Objectives
Find the radius and diameter of a circle.
Find the circumference of a circle.
Find the area of a circle.
Find the volume of a cylinder.
Find the surface area of a rectangular solid.
Find the surface area of a cylinder.

3. Find the radius and diameter of a circle.

4. Find the radius and diameter of a circle.

5. Find the radius and diameter of a circle.
Example
Find the diameter of the given circle.
Because the radius is 9 cm, the diameter is twice as long.

6. Find the radius and diameter of a circle.
Example
Find the radius of the given circle.
The radius is half the diameter.

7. Find the circumference of a circle.
The perimeter of a circle is called its circumference.
Dividing the circumference of any circle by its diameter always gives an answer close to 3.14.
This ratio of circumference to diameter is called .

8. Find the circumference of a circle.

9. Find the circumference of a circle.
Example
Example
Find the circumference of the circle. Use 3.14 for . Round to the nearest tenth.
The diameter is 38 m, so use the formula with d in it.

10. Find the circumference of a circle.
Example
Example
Find the circumference of the circle. Use 3.14 for . Round to the nearest tenth.
The radius is 11.5 cm, so use the formula with r in it.

11. Find the area of a circle.

12. Find the area of a circle.
Example
Find the area of a circle with radius 8.2 cm. Use 3.14 for . Round to the nearest tenth.

13. Find the area of a circle.
Example
Find the area of the circle. Use 3.14 for Round to the nearest tenth.
In this circle, the diameter is 10 ft. First find the radius.
Now find area.

14. Find the area of a circle.
Example
Find the area of the semicircle. Use 3.14 for Round to the nearest tenth.
First, find the area of a whole circle with a radius of 12 ft.
Divide by 2 to find the area of the semicircle.

15. Find the area of a circle.
Example
A circular rug is 8 feet in diameter. The cost of fringe for the edge is $2.25 per foot. What will it cost to add fringe to the rug? Use 3.14 for
The cost of adding the fringe is $56.52.

16. Find the area of a circle.
Example
A circular rug is 8 feet in diameter. The cost of covering the underside with a nonslip backing is $1.50 per square foot. What will it cost to add the backing to the rug? Use 3.14 for

17. Find the volume of a cylinder.

18. Find the volume of a cylinder.
Example
Find the volume of the cylinder. Use 3.14 for .
The diameter is 20 m, so the radius is 20 m ÷ 2 = 10 m. The height is 9 m.

19. Find the volume of a cylinder.
Example
Find the volume of the cylinder. Use 3.14 for Round to the nearest tenth.
The radius is 6.2 cm. The height is 38.4 cm.

20. Find the surface area of a rectangular solid.
Surface area is the area on the surface of a three-dimensional object.

21. Find the surface area of a rectangular solid.

22. Find the surface area of a rectangular solid.
Example
Find the volume and surface area of the shipping carton.
First find the volume.
Next find surface area.

23. Find the surface area of a cylinder.

24. Find the surface area of a cylinder.
Example
Find the volume and surface area of the water tank.
First find the volume.
Next find surface area.