Answer:
Volume = 35185.8 
Step-by-step explanation:
Recall the formula for the volume of a cone: 
Where R is the radius of the cone's circular base (in your case half of 80 km,(that is 40 km)
And h stands for the height of the cone (in your case 21 km)
We replace such in the formula and calculate its final value:

We round it to the number of decimals your problem request (let's say to one decimal) and also include the cubic units:
Volume = 35185.8 
Answer: x = 5/4y + 10
y = 4/5x - 8
Step-by-step explanation:
Answer:
or 0.02
Step-by-step explanation:
2% x 1 to give the answer
or
reduce it to faction like
<h2>
= 
</h2>
Use a calculator. 6 square root of 2 and 8 square root of 2. Times both of them and turns to 2304. Then 2304 square root of 2 again
Answer: y=6, x=2
Step-by-step explanation:
Substitute x=12-y/3
Isolate y, then you get 6 is y
x=12-3/3
x=2