See worked examples of performing geometric enlargements

1. Enlargements
(Dilations)

2. RECALL: To perform an enlargement
▪ plot the vertices and join them to form the object.
▪ plot the centre of enlargement.
▪ draw lines from the centre of enlargement through each vertex of the
object.
▪ measure the required distance along the line from the centre and
plot the image point.
▪ repeat for each vertex of the image.
▪ join these vertices to form the image.

3. EXAMPLE- 1

4. EXAMPLE 1
▪ On the diagram, accurately draw an enlargement of triangle ABC, by
a scale factor, k = 2, about centre, O.

5. EXAMPLE 1 solution
▪ Draw lines from the centre, C, through each vertex of the object.

6. EXAMPLE 1 solution cont’d.
▪ Since k = 2, then the distance
from the centre to each
object point MUST BE twice
the distance from the centre
to each corresponding image
point.
▪ Measure the required
distance and plot the image
vertices.
▪ Join them to form the image.

7. EXAMPLE- 2

8. EXAMPLE 2
▪ The letter ‘A’ and the point C (6,6) are shown on the grid below.
▪ On the diagram, accurately draw an enlargement of the letter ‘A’, by
a scale factor, k = 2, about centre, C (6,6).

9. EXAMPLE 2 solution
▪ Draw lines from the centre, C, through each vertex of the object.

10. EXAMPLE 2 solution cont’d.
▪ Since k = 2, then the distance
from the centre to each
object point MUST BE twice
the distance from the centre
to each corresponding image
point.
▪ Measure the required
distance and plot the image
vertices.
▪ Join them to form the image.

11. EXAMPLE- 3

12. EXAMPLE 3
▪ The triangle OPQ is shown.
▪ On the diagram, accurately
draw P’Q’, the image of the line
PQ after an enlargement with
scale factor, k = 3, and centre O.

13. EXAMPLE 3 solution
▪ Draw lines from the centre, C,
through the points P and Q.

14. EXAMPLE 3 solution cont’d.
▪ Since k = 3, then the
distance from the centre to
each object point MUST
BE three times the
distance from the centre to
each corresponding image
point.
▪ Measure the required
distance and plot the
image vertices.
▪ Join them to form the
image.

15. The End.