Patrick is using a weed killer to treat his circular lawn which a diameter of 12 metres. The weed killer instructions say to use 20 ml for every square metre of lawn to be treated. How much weed killer does he need to use? Give your answer to the nearest ml.

Question

Patrick is using a weed killer to treat his circular lawn which a diameter of 12 metres. The weed killer instructions say to use 20 ml for every square metre of lawn to be treated. How much weed killer does he need to use?  Give your answer to the nearest ml.

anonymous · Answer

area = pi*r^2
area = pi*6^2
area=36pi m^2
weed killer = (20 ml )(36 pi m^2)

anonymous · Answer

720 ml

anonymous · Answer

oops forgot the pi

anonymous · Answer

20*36*pi = answer in ml

anonymous · Answer

diameter = 12m  ==> radius = 6m

area of circle = πr^2 = 3.14 * (6m)^2 = 3.14*36m^2 = 113.04m^2

for 1 m^2 area wed killer required = 20 ml
so for 113.04m^2 area, weed killer required = (20 * 113.04) ml = 2260.8 ml = 2261 ml

anonymous · Answer

technically 2262 if you use full pi

anonymous · Answer

and dont round till the end like you're supposed to