Question

Help for exams Need to clear the traingle concepts....class 10

Answer 1

take text as reference

Answer 2

These are the notes for the chapter Triangles. Hope it helps!! :)
1. Similar Triangles : Two triangles are said to be similar if their corresponding angles are equal and their corresponding sides are proportional.

2. Criteria for Similarity : in ABC and DEF
(i) AAA Similarity 
 (ii) SAS similarity
(iii) SSS Similarty:
The proof of the following theorems can be asked in the examination :
(i) Basic Proportionality Theoren: If a line is drawn parallel to one side of a triangle to intersect the other sides in distinct points, the other two sides are divided in the same ratio.

(ii) The ratio of areas of two similar triangles is equal to the square of the ratio of their corresponding sides. 

iii) Pythagoras Theorm: In a right triangles the square of the hypotenuse is equal to the sum of the squares of the other two sides.

 (iv) Converse of pythagoras thearem— In a triangle, if the square of one side is equal to the sum of squares of other two sides then the angle opposite to the first side is a right angle