Identify the variation as direct, inverse, joint or combined.

v = rrah

direct

inverse

joint

combined

Third option.

Step-by-step explanation:

For this exercise it is important to remember that, by definition, a Joint variation is that variation in which one variable depends on two or more variables and  there are a direct relation between these variables.

In this case, you have the following equation given in the exercise:

 Let's assume that "r" and "h" are variables.

You can identify that:

So, based on this, the variation can be read as:

"V" varies jointly with the square of "r" and "h".

Therefore, you can conclude that the  given variation is: Joint.

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204