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There is 3 seperate tunnels built side by side. Each is half-cylinder that is 50,000 meters long and 4 meters high. How many cubic meters of dirt had to be removed to build these tunnels

Answer 1

3 x (1/2) x (pi x r^2 x L) + a 'little bit' more due to the two entrances.
3 x (1/2) x (pi x r^2 x L) =
3/2 x pi x (4 m)^2 x 50 km = 3.8 million m3.
So totally about 4 million m3.

Th

Answer 2

Using the formula of a cylinder...
V = pi * r² * L

But cut it in half and multiply times 3 tunnels:
V = pi * r² * L * 3/2

So:
V = pi * 4² * 50,000 * 3/2
V = 1,200,000 pi
V = 3,769,911 cubic m.
V ≈ 3.8 million cubic meters

Answer 3

the thing required is to find the volume of half cylinder
v=pi r^3 h=3.14* 4^3 *50000
v/2=3.14* 4^3 *25000
for three tunnels =3* 3.14* 4^3 *25000

Answer 4

you need to find the volume of each half-cylinder. use the formula pi*r^2*h to find the volume of the cylinder. since it is a half-cylinder you need to divide this by 2. this will get you the volume of one of the half-cylinders. to find the volume of all three you need to multiply your answer by 3.

pi * 4^2 * 50000
800,000pi <-- volume of one cylinder
800,000pi / 2 <-- volume of one half-cylinder
400,000pi
400,000pi * 3 <-- volume of all three half cylinders
1200,000pi