The perimeter is just adding all the sides together.
a.) 180 = 40 + 40 + x + x
180 = 80 + 2x Subtract 80 on both sides
100 = 2x Take 1/2 of 100 to get x
x= 50cm
b.) 1000 = 150 + 150 + x + x
1000 = 300 + 2x Subtract 300 on both sides
700 = 2x Take 1/2 of 700 to get x
x = 350
9 is the square root of 81
final answer: 9
Answer:
Step-by-step explanation:
Here's the formula for the volume of a right circular cylinder:

Here's what we are given and what we need to find:
Given that d = 10 cm, h = 20 cm, dd/dt = 1 cm/sec
Need to find dh/dt when V is constant
Since our formula has a radius in it and not a diameter but the info given is a diameter, we can use the substitution that
so

Now we can rewrite the formula in terms of diameter:
which simplifies down to

Now we will take the derivative of this equation with respect to time using the product rule. That derivative is
![\frac{dV}{dt}=\frac{\pi }{4}[d^2*\frac{dh}{dt}+2d\frac{dd}{dt}*h]](https://tex.z-dn.net/?f=%5Cfrac%7BdV%7D%7Bdt%7D%3D%5Cfrac%7B%5Cpi%20%7D%7B4%7D%5Bd%5E2%2A%5Cfrac%7Bdh%7D%7Bdt%7D%2B2d%5Cfrac%7Bdd%7D%7Bdt%7D%2Ah%5D)
Now we can fill in our values. Keep in mind that if the volume is constant, there is no change in the volume, so dV/dt = 0.
and

Multiply both sides by pi/4 to get
and solve for dh/dt:

Interpreted within the context of our problem, this means that the volume will be constant at those given values of diameter and height when the liquid in the cylinder is dropping at a rate of 4 cm/sec.
I think the answer is $1,760 so sorry if i’m wrong :/