Answer:
Part 1) 
Part 2) 
Step-by-step explanation:
Part 1) Find the value of x
we know that
Triangles CDF and FDE are similar
therefore
The ratio of its corresponding sides is proportional and its corresponding angles are congruent
so


Part 2) Find the length of DE

substitute the value of x

Answer:
1480cm³
Step-by-step explanation:
The Equation for the Volume of a Cylinder is V=Bh, where B is the area of the circle (A= πr²).
We are given all of the things we need, we just have to plug them into the equation.
First let's find B using the radius(r) which is given to be 6.4cm, so B=πr²
B=π(6.4cm)²
Plug that into a calculator to get 128.6796351cm²
Now we can plug that into the original equation, V=Bh.
V=(128.6796351cm²)h
h is also given to be 11.5cm, so lets plug that in.
V=(128.6796351cm²)(11.5cm)
You will get V=1479.815804cm³, but since we are rounding to the nearest cubic centimeter, we would round up to 1480cm³.
Did it the longer way but i hope it helps you out.... Answer: 2/3