First you need to make a line that is perpendicular to one side. The diagram is shown below. then the length of the line that is perpendicular to the triangle is

then the area of the equilateral triangle equals to

so the area would be
Answer:
$2.57
Step-by-step explanation:
divide 5,140 by 20,
5,140/20=257=2.57
Remember that the volume of a cylinder is

so we have that
![r=\sqrt[]{\frac{V}{\pi\cdot h}}=\sqrt[]{\frac{1909.92384}{3.14\cdot6.6}}=\sqrt[]{92.12}=9.6](https://tex.z-dn.net/?f=r%3D%5Csqrt%5B%5D%7B%5Cfrac%7BV%7D%7B%5Cpi%5Ccdot%20h%7D%7D%3D%5Csqrt%5B%5D%7B%5Cfrac%7B1909.92384%7D%7B3.14%5Ccdot6.6%7D%7D%3D%5Csqrt%5B%5D%7B92.12%7D%3D9.6)
so the radius is 9.6 milimeters
Very good job! They are all correct and it shows how you got the answer! ^_^ 100%