Answer:
To find the length of the third side of a triangle for class 7, you can use the Pythagorean theorem. The Pythagorean theorem states that in a right triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides.
The theorem can be written as: c^2 = a^2 + b^2, where c is the hypotenuse and a,b are the other two sides.
So, if you know the lengths of the other two sides, you can use this theorem to find the length of the third side. For example, if you know the lengths of sides a and b, you can use the following formula to find the length of side c: c = √(a^2 + b^2)
You can also use the converse of the Pythagorean theorem, which states that if the square of the length of one side is equal to the sum of the squares of the other two sides, the triangle is a right triangle.
It is always a good idea to draw a diagram to help you understand the problem and to double check the answer.
Explanation: