I believe the answer is the last option choice.


The value of x⁴ is equal to 79.8006702
The volume of a rectangular prism is always LWH=V, the cube is a special prism in that L=W=H are all equal so:
V=s^3 where s is the length of all sides...
s^3=1728
s=1728^(1/3)
s=12 units
Answer: x = 60
Step-by-step explanation:
the equation is a^2 + b^2 = c^2.
If you draw out the problem, you plug in the information into the formula, so it would be...
x^2 + 80^2 = 100^2.
80^2 = 6,400 and 100^2 = 10,000.
x^2 + 6,400 = 10,000.
You subtract 6,400 from itself and 10,000 and then you get...
x^2 = 3,600.
You square both of those and your final answer will be x = 60.
If she went 10 miles upstream in the same time as she went 20 miles downstream, that means the downstream speed is twice the upstream speed.
The speed is still water is 9 mph.
The speed of the current is c.
Going downstream, the current adds speed, so the sped downstream is 9 + c.
The speed upstream is 9 - c.
9 + c is twice 9 - c.
9 + c = 2(9 - c)
9 + c = 18 - 2c
3c = 9
c = 3
Answer: The speed of the current is 3 mph.
Check:
9 + c = 12
9 - c = 6
By taking into the account the speed of the current, the downstream speed, 12 mph, is indeed twice the upstream sped, 6 mph.