Base = Height, Let them be x.

Solve quadratic equation:
x=6, x=-2(rejected because base and height is positive)
6x6/2 =18
Answer: 27 cm
Step-by-step explanation:
We know that the volume of a cylinder is
. Since we were given the volume and radius, we can plug them in and solve for height.
[divide both sides by π]
[exponent]
[divide both sides by 25]

Now, we know that the height is 27 cm.
In the given question it is important to take note of every minute details that are given in the question. using these details the answer to the given question can be easily reached.
Let us assume the common ratio to be x.
Then
x + 9x = 81
10x = 81
x = 81/10
= 8.1
A s we already know that the ratio of chaperones to students is 1:9
Then
The number of chaperones = 1 * 8.1
= 8.1
So 8.1 chaperones were there in total. I hope you have got the answer you were looking for.