A cone with a bottom radius of 5cm and a height of 15cm is immersed in a cylindrical container with a radius of 10cm. After taking out the cone, how many cm will the water surface drop?

A cone with a bottom radius of 5cm and a height of 15cm is immersed in a cylindrical container with a radius of 10cm. After taking out the cone, how many cm will the water surface drop?

Cone volume 3.14 × 5 × 5 × 15 × 1 / 3 = 392.5
392.5÷(3.14×10×10)=1.25
A: the water surface will drop by 1.25cm

The length of the two right sides of a right triangle is 3cm and 4cm respectively, and the length of the hypotenuse is 5cm. One or two right sides of a right triangle rotate one circle as the axis to form an object of what shape? Are they equal in volume?

First, it's all cones
But the volume is different. If 3cm is taken as the rotation axis, then the volume is 1 / 3 * 3.14 * 4 * 4 * 3 =
If the rotation axis is 4cm, the volume is 1 / 3 * 3.14 * 3 * 3 * 4 =

It is known that the length of one right side of a right triangle is 3cm, and the length of the middle line on the hypotenuse is 2.5cm, so the length of another right side can be calculated

Suppose a is a right angle, O is the midpoint on the hypotenuse, ab = 3, Ao = 2.5, so the length of Ca is obtained
Solution Bo = one-half of 11 under the radical
According to the triangle similarity principle, OB: ab = Ao: CA
CA = 15 times the root of 11 and then divided by 11