Page 1 - LN

SAI International School
CLASS - X

Mathematics
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CHAPTER-6: Triangless-3Lesson Notes-3
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SUBTOPIC :Areas of similar Triangless
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Area: Amount of region bounded in a closed figure known as Area..

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Area of a triangle: xbasexheight
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Theorem-6.6
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Prove that the ratio of the areas of two similar triangles is equal to the ratio of
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t the squares of their corresponding sidess
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Given:
ABC ~ PQR
To prove:

Construction:
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Draw AD BC and PS QR..
Proof:

In triangles ADB and PSQ,

B = Q [since, ABC ~ PQR]
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ADB = PSQ = 90 [since AD BC and PS QR, by construction]

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Therefore, ADB ~ PSQQ [by AA similarity]
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Hence, [corresponding sides of similar triangles] (2)
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