Question

how many theorms are there in class 9th chapter 7 traingles​

Answer 1

Answer:

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Step-by-step explanation:

Theorem 1: The sum of all the three interior angles of a triangle is 180 degrees.

Theorem 2: The base angles of an isosceles triangle are congruent.

Or

The angles opposite to equal sides of an isosceles triangle are also equal in measure.

Theorem 3: The measure of the exterior angle of a triangle is equal to the sum of the corresponding interior angles.

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Answer 2

Answer:

There are 8 theorems

Step-by-step explanation:

• Theorem 7.1 (ASA congruence rule) : Two triangles are congruent if two angles  and the included side of one triangle are equal to two angles and the included side of other triangle.

• Theorem 7.2 : Angles opposite to equal sides of an isosceles triangle are equal. This result can be proved in many ways. One of  the proofs is given here.
• Theorem 7.3 : The sides opposite to equal angles of a triangle are equal.
• Theorem 7.4 (SSS congruence rule) : If three sides of one triangle are equal to the three sides of another triangle, then the two triangles are congruent.
• Theorem 7.5 (RHS congruence rule) : If in two right triangles the hypotenuse  and one side of one triangle are equal to the hypotenuse and one side of the  other triangle, then the two triangles are congruent.
• Theorem 7.6 : If two sides of a triangle are unequal, the angle opposite to the  longer side is larger (or greater).
• Theorem 7.7 : In any triangle, the side opposite to the larger (greater) angle is  longer.
• Theorem 7.8 : The sum of any two sides of a  triangle is greater than the third side.