Shape and Measurement

[dinosaur93]

How to find the radius and the height of the inside of the tank given the following specs?

[seretide]

Well I'm not sure if this is right, but I'm guessing...

1. Radius of inside will be equal to 0.65m. Convert 1.5m to cm = 150cm. Subtract 10cm for each side wall (total 20cm). Diameter of inside is therefore 130cm. Radius is then equal to 65cm or 0.65m.

2. The height is equal to 1.64m. Convert 1.8m to cm - 180cm. Subtract 8cm from each side, top and bottom (total 16cm). Height is now 164cm which is 1.64m.

I think this is right.

[dinosaur93]

kindly pls tell me if Im doing it correctly or not!

Question
What is the volume of water this tank can hold when completely full? (Answers in litres)
V= r²H
V= *65²*164
V= 2,176.80955 L

Question
What is the volume of concrete required to make this tank? (Answer in litres)
V= r²H
V= *75²*180
V= 3,180.862562 L

Question
What is the TSA of the outside of the tank (including the top and bottom, answer in m²)
TSA = 2r(r+H )
TSA = 20.75(0.75+1.8 )
TSA = 12.0165919m²

Question
A circular hole of radius 30cm is put in the top of the tank. By what percentage does this decrease the volume of concrete required?
V= r²H (?)
V= 508.938099 L
3,130x=509
therefore 16% decrease (?)


Question
A budget version of the tank is made will all dimensions including the thickness of the wall reducing by a factor of 0.6. What is the volume of water this new tank can hold?
 

[seretide]

The first seems fine.

Although for the second, you found the volume if the tank did not have its boundaries inside. What you would need to do is find the volume;

1. Find volume of cylinder shape at the bottom that is;
V= pi x r^2 x h
V= pi x 65^2 x 8
Then x 2 because there is the top and bottom

2. Then add that with the volume of the sides which i actually don't know if possible to find. I think there is formula, I'll have to check back with you
 

[dinosaur93]

tnx heaps bro!

[dinosaur93]

How do you do this Q?

A budget version of the tank is made will all dimensions including the thickness of the wall reducing by a factor of 0.6. What is the volume of water this new tank can hold?

[dinosaur93]

anyone?

Help pls!

I need this badly!

tnx ppl

[seretide]

I think by being reduced by 0.6 --> 6/10 ? So 6/10 of the actual thickness is removed? Not sure