(KS3, Year 7)

An enlargement resizes a shape. An enlargement makes a shape larger or smaller. An enlargement is a type of transformation.

A Real Example of an Enlargement

It is easier to understand enlargement with an example. The diagram below shows an enlargement of a shape. The shape before the enlargement (called the object) is in light blue. The shape after the enlargement (called the image) is in dark blue:enlargement_exampleIn this example, the shape has been enlarged with a center of enlargement (shown as a red cross) at the origin.

Properties of Enlargement

  • Each side of the object is scaled by a scale factor. If an enlargement has a scale factor of 2, each side of the image is 2 times larger than the sides of the object.
  • The length of sides remain in the same proportion to each other.
  • Each line in the image is parallel to the corresponding line in the object.
  • All angles remain the same in the object and the image. properties_of_enlargement_angles

Enlarged Shapes Are Similar Shapes...

If a shape is enlarged, the shapes are similar. Similar shapes are the same shape but not the same size. similar_shapes_explained

...But Not Congruent Shapes

Congruent shapes are the same shape and the same size. congruent_shapes_explained If a shape has only been translated, reflected or rotated (or some combination of all three) then the shape is congruent.
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This page was written by Stephen Clarke.