Volume of Cones

Volume of Cones Reteach You can use your knowledge of how to find the volume of a cylinder to help find the volume of a cone. This cone and cylinder have congruent bases and congruent heights. Volume of Cone =

1 Volume of Cylinder 3

Use this formula to find the volume of a cone. 1 V = Bh 3 Complete to find the volume of each cone.

1.

2.

radius r of base = ____ in.

radius r =

1 diameter = ____ cm 2

V=

1 Bh 3

V=

1 Bh 3

V=

1 2 (πr )h 3

V=

1 2 (πr )h 3

V=

1 (π × ____ ) × ____ 3

V=

1 (π × ____ ) × ____ 3

V=

1 (____) × ____ 3

V=

1 (____) × ____ 3

V = ____ × ____

V = ____ × ____

V = ________

V = ________

V ≈ ____ in3

V ≈ ____ cm3

LESSON

13-2

Volume of Cones Reading Strategies: Use Diagrams

Reading a diagram accurately is important when solving problems.

THINK! • The base is shaded to show its area. • The diameter and the radius of the base are shown by a solid line. • The height of the cone is shown by a dashed line. • Find the area of the base by using the formula B = πr2. • Check the diagram to see if it shows the diameter or the radius of the base of the cone. • The formula asks for the radius. Remember that the diameter is twice the radius. So, d d = 2r and r = 2

Use the diagrams to answer the questions. Use 3.14 for π. Round your answer to the nearest tenth, if necessary. 1. Does the diagram of Cone A show the radius or the diameter of the base? _________________________________________________

2. What is the radius of the base of Cone A? _________________________________________________

3. What is the area of the base of Cone A? _________________________________________________

4. What is the height of Cone A? _________________________________________________

5. What is the volume of Cone A? _________________________________________________

6. What is the volume of Cone B?