1. ©G Dear2008 – Not to be sold/Free to use
Similarity
Rule 02
Stage 4 - Year 9
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©G Dear2008 – Not to be sold/Free to use

2. We only need to show two, why?
Similar Triangles 2
If 3 angles of one triangle are equal to 3 angles of another triangle, the 2 triangles are similar.
We only need to show two, why? A
All angles of triangle A are equal to all angles in triangle B. B
They are similar

3. All angles of triangle A are equal to all angles in triangle B.
Similar Triangles 2
If 3 angles of one triangle are equal to 3 angles of another triangle, the 2 triangles are similar.
60o
60o A
30o B
All angles of triangle A are equal to all angles in triangle B.
30o
They are similar

4. Formal Solution 2  ΔABC ||| ΔDEF Label each triangle.
If 3 angles of one triangle are equal to 3 angles of another triangle, the 2 triangles are similar. A
A = D B
30o
60o C
30o
60o
B = E D
C = F
Label each triangle.
 ΔABC ||| ΔDEF
(equiangular) E F