Congruence and Similarity (II) 9.29
congruent figures ΌഃྡҖ
9.3 Congruent Plane Figures
In Book 1B Chapter 10, we learnt that if two triangles can fit exactly,
it means that they have the same shape and size. This method can also be
applied to other figures.
e.g. The following figures X and Y can fit exactly. It means that they
have the same shape and size.
Y
X
Place X onto Y
(Rotate the figures
or turn them over
if necessary)
X, Y fit exactly
In Geometry,
if two figures have the same shape and size,
they are called congruent figures.
In the above example, figures X and Y are a pair of congruent figures.
Quick Quiz
State whether each of the following pairs of figures are congruent.
1. 2.
Yes�� No Yes�� No
3. 4.
Yes�� No Yes�� No
✂
For simplicity, 'plane figures'
refers to 'figures' in this
chapter.
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Interesting Maths
If we take passport photo
using the machine below,
the four photos obtained are
congruent.