Answer:
The theorem is Pythagoras theorem.
Step-by-step explanation:
Given the cone has a lateral surface with a length of 13 units. To find the volume of cone, the height is needed then we have to tell the theorem which is used to find the height if radius is known.
As the triangle AOB form a right angled triangle and if the slant height i.e l and radius r is known then in order to find height we can apply the Pythagoras theorem which can be stated as
The square of side hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides of the triangle.
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