A paint can holds 2.5litres of paint and is 18cms tall. Work out the radius

Guest Apr 22, 2015

#1**+13 **

A litre is 1000 cm^{3}

Volume = pi*r^{2}*h where r is radius and h is height, so

pi*r^{2}*18 = 2500 (we have to turn the litres into cm^{3})

Divide both sides by 18pi

r^{2} = 2500/(18pi)

Take the square root of both sides

r = 50/√(18pi)

$${\mathtt{r}} = {\frac{{\mathtt{50}}}{{\sqrt{{\mathtt{18}}{\mathtt{\,\times\,}}{\mathtt{\pi}}}}}} \Rightarrow {\mathtt{r}} = {\mathtt{6.649\: \!038\: \!006\: \!690\: \!545\: \!1}}$$

So the radius is approximately 6.65cm

.

Alan
Apr 22, 2015

#1**+13 **

Best Answer

A litre is 1000 cm^{3}

Volume = pi*r^{2}*h where r is radius and h is height, so

pi*r^{2}*18 = 2500 (we have to turn the litres into cm^{3})

Divide both sides by 18pi

r^{2} = 2500/(18pi)

Take the square root of both sides

r = 50/√(18pi)

$${\mathtt{r}} = {\frac{{\mathtt{50}}}{{\sqrt{{\mathtt{18}}{\mathtt{\,\times\,}}{\mathtt{\pi}}}}}} \Rightarrow {\mathtt{r}} = {\mathtt{6.649\: \!038\: \!006\: \!690\: \!545\: \!1}}$$

So the radius is approximately 6.65cm

.

Alan
Apr 22, 2015