There are actually 2 answers, 3 and -3. Although if you put it in a calculator, it would show "math error" or undefined. That's because the index is even (4) and the radicand is negative (-81)

4 0

3 years ago

Solve 3x2 − x = 10

Crazy boy [7]

Option number 2 I think.

3 0

2 years ago

A series of three? separate, adjacent tunnels is constructed through a mountain. Its length is approximately 25 kilometers. Each

Nadya [2.5K]

Answer:

$312.5\pi \text{ km}^3\approx 981.75\text{ km}^3$

Step-by-step explanation:

We have been given that a series of 3 separate, adjacent tunnels is constructed through a mountain. Its length is approximately 25 kilometers.

Each of the three tunnels is shaped like a half-cylinder with a radius of 5 meters.

Since we know that volume of a semicircular or a half cylinder is half the volume of a circular cylinder.

$\text{Volume of a semicircular cylinder}=\frac{\pi r^2h}{2}$ , where,

r = Radius of cylinder,

h = height of the cylinder.

Upon substituting our given values in volume formula we will get,

$\text{Volume of a semicircular cylinder}=\frac{\pi (5\text{ km})^2*25\text{ km}}{2}$

$\text{Volume of a semicircular cylinder}=\frac{\pi*25\text{ km}^2*25\text{ km}}{2}$

$\text{Volume of a semicircular cylinder}=\frac{\pi*625\text{ km}^3}{2}$

$\text{Volume of a semicircular cylinder}=\pi*312.5\text{ km}^3$

$\text{Volume of a semicircular cylinder}=981.74770\text{ km}^3$

Therefore, the volume of earth removed to build the three tunnels is $312.5\pi \text{ km}^3\approx 981.75\text{ km}^3$ .

4 0

2 years ago