HCM2 E24.1A Enlargement

Grade 7

Exercise 24.1A Enlargement

By Ben Chen

Multiple Select

Which 3 types of transformation did we study earlier this year?

• Enlargement

• Reflection

• Rotation

• Translation

Transformations

In Chapter 11 you studied reflection, rotation, and translation symmetry, all of which are types of transformation. In each of these cases the final image is the same size as the original object. All that changed was the position and orientation of the object.​

Multiple Choice

Reflection, rotation, and translation only change only the position and orientation of the final image.

• True

• False

Enlargement

Another type of transformation is enlargement. With enlargement, the final image usually has a different position and size to the original object.

Multiple Select

Which 2 properties of the original object are changed with enlargement?

• Different color

• Different position

• Different shape

• Different size

However, simply stating that the size changes is misleading. In the examples below, the picture A is the original object. Picture B shows the object stretched horizontally and picture C shows it stretched vertically.​

Multiple Choice

In what direction was picture A stretched into picture C?

• Picture C is picture A stretched horizontally

• Picture C is picture A stretched vertically

These stretches are not considered to be enlargements. For an object to be enlarged, its lengths must all be multiplied by the same amount.

For example​, here, both the horizontal and vertical lengths have been multiplied by 2. We say that the object has been enlarged by a scale factor of 2.

Multiple Choice

Picture A to picture B is an example of enlargement.

• True

• False

In an enlargement, the number which multiplies the lengths is called the scale factor of enlargement.

​

​​

​

​

​

​

​Enlarged by a scale factor of 0.5

​Worked example

Triangle Y is an enlargement of triangle X.

Calculate the scale factor of enlargement.​

​Worked example​

Lengths of triangle X are:

1 unit, 2 units, and √5 units.

​

​Lengths of triangle Y are:

3 units, 6 units, and 3√5 units.

​

Each of the lengths of triangle Y is three times that of triangle X. Therefore the scale factor of enlargement is 3.​

Exercise 24.1A

In each of the following diagrams, shape B is bigger than shape A.

a) ​Decide whether B is an enlargement of A.

b) If B is an enlargement of A, calculate the scale factor of enlargement.​

Multiple Choice

Shape B is an enlargement of A.

• True

• False

Multiple Choice

The scale factor of enlargement is...

• 2

• 3

• 4

• 5

Multiple Choice

Shape B is an enlargement of A.

• True

• False

Multiple Choice

Shape B is an enlargement of A.

• True

• False

Multiple Choice

The scale factor of enlargement is...

• 2

• 3

• 4

• 5

Multiple Choice

Shape B is an enlargement of A.

• True

• False

Multiple Choice

The scale factor of enlargement is...

• 2

• 3

• 4

• 5

Multiple Choice

Shape B is an enlargement of A.

• True

• False

Multiple Choice

Shape B is an enlargement of A.

• True

• False

Multiple Choice

The scale factor of enlargement is...

• 0.5

• 1.5

• 2.5

• 3.5

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