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Revision Notes

Similarity Of Triangles — Revision Notes

NIOS · Class 10 · Maths

Similarity Of Triangles revision notes for NIOS Class 10 Maths: 4 topics in quick points. Part of the NIOS Class 10 Maths syllabus.

42 questions28 flashcards10 formulas & key relations5 concepts

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Key Topics to Revise

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1. Similar Plane Figures and Similar Objects

  • Similar objects have the same shape but not necessarily the same size.
  • Two polygons are similar only if both corresponding angles are equal and corresponding sides are proportional.
  • The symbol ~ means 'is similar to'.
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2. Basic Proportionality Theorem and Its Converse

  • If a line is drawn parallel to one side of a triangle and intersects the other two sides, the two sides are divided proportionally.
  • In triangle ABC, if DE is parallel to BC, then AD/DB = AE/EC.
  • The converse is also true: if a line divides any two sides of a triangle in the same ratio, then the line is parallel to the third side.
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3. Angle Bisector Theorem

  • The bisector of an interior angle of a triangle divides the opposite side in the ratio of the sides containing the angle.
  • If AD bisects angle A in triangle ABC, then BD/DC = AB/AC.
  • This theorem is useful when one side of a triangle is divided by an angle bisector.
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4. Similarity Criteria for Triangles

  • AAA criterion: if corresponding angles of two triangles are equal, the triangles are similar.
  • It is enough to check two angles, because the third angle is automatically equal since the angle sum is 180°.
  • SSS criterion: if corresponding sides of two triangles are proportional, the triangles are similar.

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Full Notes

Key Concepts

Objects with the same shape butIf a line is drawn parallelIf a line divides any twoThe bisector of an interior angleIf the corresponding angles of two

Frequently Asked Questions

What are the important topics in Similarity Of Triangles for NIOS Class 10 Maths?
Key topics in Similarity Of Triangles include Similar Plane Figures and Similar Objects, Basic Proportionality Theorem and Its Converse, Angle Bisector Theorem, Similarity Criteria for Triangles. Study these first, then practise questions on each for the NIOS Class 10 board exam.
How should I revise Similarity Of Triangles for the NIOS Class 10 board exam?
Learn the core ideas first, then work through the 42 practice questions on Similarity Of Triangles. Revise definitions regularly and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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