Two objects are similar if they have the same shape, so that one is an enlargement of the other.
Two objects are congruent if they are the same shape and size.
In an enlargement or reduction
Triangle A is an enlargement of C, with a scale factor of 2
Triangle C is a reduction of A, with a scale factor of ½
Triangle B is an enlargement of C , with a scale factor of 3
Triangle B is an enlargement of A,
with a scale factor of 1.5
Its scale factor may be written as
Two shapes are said to be similar if one is a scaled version of the other.
This means that
Are these dominoes similar?
(All right angles, so equal)
The dominoes are similar
Start with the shape containing the missing side.
Calculate the size of side x.
For any triangle
If pairs of corresponding angles are equal,
then ratios of lengths of corresponding sides are equal and the triangles are similar.
Conversely, if ratios of lengths of corresponding sides are equal, then pairs of corresponding angles are equal , and the triangles are similar.
Given AD is 15 cm , AB is 12 cm and DE is 10cm,find the length of BC.
BC is parallel to DE , so the corresponding angles are equal.
This means that triangles ABC and ADE are similar.
Split the triangles into their components
Given that shape A is enlarged by a scale factor of 2,
find the size of the Area of shape B.
Wiffoff deodorant is usually sold in 200 ml cans.
A new size can is made, with half of the dimensions of the old one.
Calculate the volume of the new can.
The new can has a volume of 25 ml.