New
New
Year 10
Higher

The effect of enlargement on the volume of a 3D shape

I can understand the effect of an enlargement on the volume of a 3D shape.

New
New
Year 10
Higher

The effect of enlargement on the volume of a 3D shape

I can understand the effect of an enlargement on the volume of a 3D shape.

Lesson details

Key learning points

  1. An enlargement means the object and image are similar.
  2. All lengths in the object have been multiplied by the scale factor.
  3. Using index laws, this means the volume has been multiplied by the scale factor cubed.

Common misconception

I will get different linear scale factors if a measure corresponding lengths in cm vs inches.

Scale factors do not have dimensions, and aren't linked to specific units. If one length is 23 cm (9 inches), and a corresponding length is 69 cm (27 inches), then the scale factor between them is 3, regardless of whether we measured in cm or inches.

Keywords

  • Similar - Two shapes are similar if the only difference between them is their size. Their side lengths are in the same proportions.

  • Invariant - A property of a shape is invariant if that property has not changed after the shape is transformed.

  • Enlargement - Enlargement is a transformation that causes a change of size.

  • Scale factor - A scale factor is the multiplier between similar shapes that describes how large one shape is compared to the other.

  • Volume - Volume is the amount of space occupied by a closed 3D shape.

Task B, question 2 can be more easily answered by calculating the maximum possible volume scale factor from the scale model to the real car, then cube rooting the volume scale factor to find the maximum possible linear scale factor. This method will be explicitly covered in lesson 6 of this unit.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
The transformation that causes a change in of the object is enlargement.
Correct Answer: size
Q2.
Rectangles A and B are similar. What is the area scale factor from A to B?
An image in a quiz
$$\frac{1}{25}$$
$$\frac{1}{5}$$
5
Correct answer: 25
125
Q3.
Shapes P and Q are similar. The perimeter of shape P is 18 cm and the perimeter of shape Q is 72 cm. The area scale factor from P to Q is .
An image in a quiz
Correct Answer: 16
Q4.
Sectors E and F are similar. The area of sector E is 30π cm². What is the area of sector F?
An image in a quiz
36π cm²
42π cm²
60π cm²
90π cm²
Correct answer: 120π cm²
Q5.
Sectors E and F are similar. The area of shape E is 24π cm² and the area of sector F is 150π cm². The radius of sector F is cm.
An image in a quiz
Correct Answer: 15, 15 cm
Q6.
Triangles L and M are similar. The area of triangle M is 54 cm². What is the perimeter of triangle M?
An image in a quiz
30 cm
33 cm
Correct answer: 36 cm
42 cm
48 cm

6 Questions

Q1.
__________ is the amount of space occupied by a closed 3D shape.
area
perimeter
Correct answer: volume
Q2.
A cuboid of dimensions 2 cm by 3 cm by 10 cm is enlarged by a scale factor of 3. Work out the volume of the enlarged cuboid.
An image in a quiz
480 cm³
540 cm³
1080 cm³
Correct answer: 1620 cm³
Q3.
Shape A is a 3D shape. Shape A is enlarged by scale factor 3 to give shape B. What is the volume scale factor from A to B?
$$\sqrt 3$$
$$3$$
$$6$$
$$9$$
Correct answer: $$27$$
Q4.
Match each linear scale factor to correct the volume scale factor.
Correct Answer:Linear scale factor: $$2$$,Volume scale factor: $$8$$

Volume scale factor: $$8$$

Correct Answer:Linear scale factor: $$4$$,Volume scale factor: $$64$$

Volume scale factor: $$64$$

Correct Answer:Linear scale factor: $$5$$,Volume scale factor: $$125$$

Volume scale factor: $$125$$

Correct Answer:Linear scale factor: $$10$$,Linear scale factor: $$1000$$

Linear scale factor: $$1000$$

Q5.
Prism S and prism T are similar. What is the scale factor of enlargement from prism S to prism T?
An image in a quiz
$$\frac {3}{2}$$
$$\frac {9}{4}$$
$$\frac {4}{9}$$
$$\frac {8}{27}$$
Correct answer: $$\frac {27}{8}$$
Q6.
Prism A and prism B are similar. The end face of prism A has an area of 15 cm². The volume of prism B is cm³.
An image in a quiz
Correct Answer: 1440, 1,440