Volume and capacity
Find the volume of prisms, cylinders, pyramids, cones and spheres; convert between volume and capacity; apply the trapezoidal rule to estimate the volume of irregular solids.
Worked examples
Volume of a cylinder
Straightforward
Problem
A cylindrical water tank has a radius of m and a height of m. Find the volume of the tank. Give your answer to 2 decimal places.
1
Write the formula for the volume of a cylinder.
2
Identify the values: m, m.
3
Substitute the values and evaluate.
m³
Answer
m³
Volume of a cone and converting to capacity
Moderate
Problem
A conical container has a radius of cm and a perpendicular height of cm. Find the volume of the container, then state the capacity in millilitres. Give the volume to 2 decimal places.
1
Write the formula for the volume of a cone.
2
Identify the values: cm, cm.
3
Substitute and evaluate.
cm³
4
Convert to millilitres using cm mL.
cm³ mL
Answer
cm³ mL
Volume using the trapezoidal rule
Challenging
Problem
A section of a river has an irregular cross-section. The width at the front is m and the width at the rear is m, with a perpendicular distance of m between the two measurements. The section of river being measured is m long. Use the trapezoidal rule to estimate the volume of water in this section.
1
Identify the values for the trapezoidal rule: m, m, m.
2
Apply the trapezoidal rule to estimate the cross-sectional area.
m²
3
Multiply the cross-sectional area by the length of the section to find the volume.
m³
Answer
m³
Practise
Q1·Straightforward
A rectangular storage crate has a length of m, a width of m, and a height of m. Find the volume of the crate.
Explanation
m³
Q2·Straightforward
A triangular prism has a triangular cross-section with a base of m and a perpendicular height of m. The prism is m long. Find the volume of the prism.
Explanation
Area of triangle m². m³.
Q3·Straightforward
A cylindrical pipe has a radius of cm and a length of cm. Find the volume of the pipe. Give your answer to 2 decimal places.
Explanation
cm³.
Q4·Straightforward
A cylindrical water tank has a radius of m and a height of m. Find the volume of the tank. Give your answer to 2 decimal places.
Explanation
m³.
Q5·Moderate
A square pyramid has a base of side length m and a perpendicular height of m. Find the volume of the pyramid.
Explanation
Base area m². m³.
Q6·Moderate
A conical funnel has a radius of cm and a perpendicular height of cm. Find the volume of the cone. Give your answer to 2 decimal places.
Explanation
cm³.
Q7·Moderate
A spherical ball has a radius of cm. Find the volume of the ball. Give your answer to 2 decimal places.
Explanation
cm³.
Q8·Moderate
A rectangular fish tank has internal dimensions cm long, cm wide, and cm tall. Find the capacity of the tank in litres. (Use cm mL.)
Explanation
cm³ mL L.
Q9·Challenging
A concrete retaining wall has an irregular cross-section. The depth at the front is m and the depth at the rear is m, with a perpendicular distance of m between the two measurements. The wall is m long. Use the trapezoidal rule to estimate the volume of concrete in the wall.
Explanation
m². m³.
Q10·Challenging
A section of an irrigation channel has an irregular cross-section. The width at the top is m and the width at the base is m, with a perpendicular depth of m. The section is m long. Use the trapezoidal rule to estimate the volume of water the section holds.
Explanation
m². m³.
Q11·Challenging
An earth embankment has an irregular cross-section. The width at the top is m and the width at the base is m, with a perpendicular height of m. The embankment is m long. Use the trapezoidal rule to estimate the volume of earth in the embankment.
Explanation
m². m³.
Q12·Challenging
A garden bed has an irregular cross-section. The width at the front edge is m and the width at the rear edge is m, with a perpendicular distance of m between the two edges. The garden bed is m long. Use the trapezoidal rule to estimate the volume of soil needed to fill the garden bed.
Explanation
m². m³.