A* question on mymaths help

Please can someone explain to me how to do this. Ive done the hwk 6 times and still get this wrong :-(

thank uin advance!

You know the slant height and diameter of the cone, use that to work out the volume. Then, rearrange the sector equation for theta.

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we can only see where you are going wrong if you indicate your method and working out

so far ive got... Volume of a cone = 1/3 pi r squared times height.
Then 1/3 pi 4.7 squared times 12 which is 277.59.. And thats all i have got

SORRY THAT DOESNT MKESENSE NOW THE SA IS PI TIMES R TIMES L

You have r and l though. What doesn't make sense?

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I don't know if this method would work but it seemed right in my head so give it a go if you want.

1. Imagine the bottom of the cone as a circle and, using the base of the triangle in the second picture (diameter of the circle), we should be able to work out the circumference of the circle.
2. Since the circumference of the circle is equal to the arc length of the sector in the third picture, using the equation for the arc length (L = θ × r) we should be able to work out the value of x in radians.
3. Convert the value of x from radians into degrees.

I tried this method and the answer seems to be believable.

Thank you for your help , I tried the first part with the diameter and got 14.7654, then I was a little puzzled as I have never come across thisL = θ × r) maybe the question is too beyond me.. ive only ever done x/360 times pi r squared for the sector. but thank u for ur help anyway, I may just speak to my teacher at school about this as I need a really basic step by step method and thru a computer its hard..