Enlargement (or dilation) changes the size of a shape while keeping its shape the same.

Important terms:

• Centre of enlargement – fixed point
• Scale factor – multiplier
  • 1 enlarges
  • 0–1 reduces
  • negative values flip the image

Worked Example 1

Enlarge point A(2,3) by scale factor 2, centre at (0,0):

New point: (4,6)

Worked Example 2

Enlarge triangle with vertices
A(-4,-2), B(-3,-5), C(-5,-5)
by scale factor 3, centre (-6,-5):

New coordinates:
P(4, 0)
Q(3, -5)
R(-3, -5)