When Triangle will be Revolved about its hypotenuse then,Circumference of Base of cone=Base of triangle =2 pie r = 15 cmso, r=(15)/(2 pie)=radius of conealso,h=height of cone=height of triangle =20cmnow,volume of formed cone=(1/3) (pie) (r^2) (h)=(2625)/(22) cm^3=119.3 cm^3

Given:
- The sides of the right triangle are 15 cm and 20 cm.

To find:
- The volume of the double cone formed when the triangle is revolved about its hypotenuse.

Solution:

Step 1: Find the length of the hypotenuse.
Using the Pythagorean theorem, we can find the length of the hypotenuse (c) of the right triangle.
c² = a² + b²
c² = 15² + 20²
c² = 225 + 400
c² = 625
c = √625
c = 25 cm

Step 2: Find the radius of the base of the cones.
The radius of the base of each cone is half the length of the hypotenuse.
Radius (r) = c/2
r = 25/2
r = 12.5 cm

Step 3: Find the height of each cone.
The height (h) of each cone is the length of the right triangle's side that is not the hypotenuse.
Since the given triangle is a right triangle with sides 15 cm and 20 cm, either of these sides can be considered as the height.
Taking 15 cm as the height (h).

Step 4: Calculate the volume of each cone.
The volume (V) of a cone can be calculated using the formula:
V = (1/3) * π * r² * h
V = (1/3) * 3.14 * (12.5)² * 15
V = (1/3) * 3.14 * 156.25 * 15
V = 3.14 * 156.25 * 5
V = 2453.125 cm³

Step 5: Calculate the total volume of the double cone.
Since we have two identical cones, the total volume of the double cone is twice the volume of a single cone.
Total Volume = 2 * V
Total Volume = 2 * 2453.125
Total Volume = 4906.25 cm³

Therefore, the volume of the double cone formed when the right triangle is revolved about its hypotenuse is 4906.25 cm³.