Question

The guttering hold up to 20 litre of rain water. Work out the length of guttering in meters if the diameter is 11.5cm.

Answer 1

Answer:

1107.0213 cm

Step-by-step explanation:

Assuming this gutter is half a cylinder,

Volume of half a cylinder = 0.5(πr²l)²

where, Volume = 20l, π = 3.142, r = 0.5(11.5) and l = ?

But, the other units are in cm while the Volume is in liters, so let's convert the liters to cm³

It would be easier to convert the liters to m³ then to cm³ rather than converting directly. So,

1000 L = 1 m³

     1 L = ?

1 ÷ 1000 = 0.001 m³

      1 m³ = 1,000,000cm³

0.001 m³ = ?

0.001 x 1,000,000 = 1000 cm³

So, if 1 L = 1000 cm³

      20 L = ?

20 x 1000 = 20,000 cm³

Thus, 20,000 = 0.5(3.142 x 0.5(11.5) x l)

20,000 = 0.5(3.142 x 5.75 x l)

20,000 = 18.0665l

Make l the subject and divide both sides by 18.0665

length = 1107.0213 cm