Page 62 - Mathematics_Form_Two

Similarity

(d) Lemalai, who is 190 cm tall, did (a) Find the scale factor of VWX∆
the same procedure described to ABC.∆
above. His shadow is 150 cm (b) Find the ratio of the area of
long. How far was he from the ∆ VWX to area of ABC.∆
tree?
(c) Explain how the results in (a)
FOR ONLINE READING ONLY
are related with the results in (b)
6 Study the following figure and show
Mathematics for Secondary Schools Chapter summary
that ACB∆
DCE.
∆


1� AA Similarity theorem

If the correspondence between
triangles is such that two pairs of
corresponding angles are equal,
then the triangle are similar.
2� SAS Similarity theorem
7. Show with reasons that the
following triangles are similar. If the correspondence between two
triangles is such that the lengths of
(a) two pairs of corresponding sides

are proportional and the included
angles are equal, then the triangles
are similar.

3� SSS Similarity theorem
If the correspondence between
(b) two triangles is such that the

lengths of corresponding sides are
proportional, then the triangles are

similar.
4. Similar figures have the same shape.
5. In similar figures, the ratios of the
lengths of corresponding sides are
8. In the following triangles, equal. That is, corresponding sides
∆ ABC  ∆ VWX. are proportional. The value of

the ratio is called the constant of
proportionality or scale factor.

6. The symbol used to indicate
similarity between figures is " ".

56
Student's Book Form Two

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MATHEMATIC F2 v5.indd 56
MATHEMATIC F2 v5.indd 56 11/10/2024 20:11:43