Class 10 Maths - HARYANA
Triangles
The Chapter 'Triangles' in Class 10 Mathematics for the Haryana Board (BSEH) builds upon the foundational knowledge of triangles from Class 9, focusing heavily on the concept of similarity of figures. Students learn the crucial Basic Proportionality Theorem (Thales's Theorem) and its converse, along with various criteria for similarity of triangles such as AAA, SSS, and SAS. The chapter also covers the relationship between the areas of two similar triangles and applies Pythagoras's Theorem to solve complex geometric problems. Mastering this chapter is essential for scoring high in geometry sections of the board exams.
Start Learning FreeKey Concepts
Similar Figures
Figures that have the same shape but not necessarily the same size are called similar figures. All congruent figures are similar, but the converse is not true.
Thales Theorem (Basic Proportionality Theorem)
If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, then the other two sides are divided in the same ratio.
Criteria for Similarity of Triangles
Triangles are similar if their corresponding angles are equal (AAA criterion) or if their corresponding sides are in the same ratio (SSS and SAS criteria).
Areas of Similar Triangles
The ratio of the areas of two similar triangles is equal to the square of the ratio of their corresponding sides.
Pythagoras Theorem
In a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
Important Formulas
Board Exam Info
In the Haryana Board (BSEH) Class 10 Mathematics examination, the 'Triangles' chapter typically carries around 6 to 8 marks. Questions frequently include 1-mark objective questions, 2-mark short-answer proofs (like Thales Theorem), and 4-mark long-answer questions involving numerical applications of Pythagoras theorem or similarity criteria.
Frequently Asked Questions
Congruent triangles have both the same shape and the exact same size (equal sides and angles), whereas similar triangles have the same shape and equal corresponding angles, but their sizes can be different with proportional sides.
Yes, the proof of the Basic Proportionality Theorem (Thales Theorem) is one of the most frequently asked long-answer questions in the Haryana Board exams.
Examine the given information: if all three sides are known, use SSS; if two sides and the included angle are given, use SAS; and if two pairs of angles are equal, use AAA.
Learn Triangles with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards