Everything Maths Grade 10

122 = 2

p

3

2

+H^2

H^2 = 130

)H=

p

130 cm

Step 3: Calculate the volume of the pyramid

V=

1

3



1

2

bhbH

=

1

3

 16

p

3 

p

130

=105,3 cm^3

Step 4: Write the final answer

The volume of the triangular pyramid is 105,3 cm^3.

Worked example 14: Finding the volume of a cone

QUESTION

Find the volume of the following cone (correct to 1 decimal place):

3 cm

11 cm

SOLUTION

Step 1: Find the area of the base

area of circle=r^2

= 32

= 9cm^2

444 13.3. Right pyramids, right cones and spheres