an open cylindrical concrete water tank has an external diameter of 12m and an external height of 15m. the thickness of the concrete is 8cm. calculate the volum

Question

well I don't really know what to write for a description so yeah I just need help on this one question please

Answer 1

Hey Jaye,

 

First, you must know how volume is defined: Area x height.  In this case, it will be Area of circle and its height.

 

Area of circle = πr²    diameter = 2 x radius  radius = diameter / 2

 

For this cylinder, there is a thickness around the cylinder.  Therefore, you have to subtract 8cm from each end.  This will be inner diameter.

 

12m - 8cm(2) = 1200m - 0.08(2) = 11.84m  (new diameter)   Note: 1m = 100cm  or 1cm = 0.01m

 

or 12/2 - 0.08 = (external diameter / 2) - 0.08 (thickness)

6 (external radius) - 0.08 (thickness) = 5.92 (inner radius)

 

(Since it is 8cm, 8 x 0.01 x 2 = 0.16.  This is the number you have to subtract from original)

 

So, you have inner diameter (11.84m) and height (15m).  The radius of inner circle will be 11.84/2 = 5.92m

 

And here is the equation: πr² (area of inner-circle) x height

 

π(5.92)² x 15 = 525.696π m³    If you have to multiply π, then it will be 1650.68544 m³

 

The final unit of the volume is cubic units (always).  In this case, it will be cubic meters.

 

 

 

I hope you understood.  Good luck to you.

 

Yohan Chu   (LV  NV)