How do i find angle x

Knowing the diameter for the top of the wrapper, you can work out the circumference at that point. This is the length of arc for the sector....

Reply 3

ombtom

Original post by Appazap

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Could someone please explain these maths questions and tell me how to work them out because i am completely lost.
Thanks :smile:

Second question: height of cylinder = 6*2.7 = 16.2cm. Volume of cylinder = pi*r^2*h. :smile:

Reply 4

Original post by ghostwalker

Knowing the diameter for the top of the wrapper, you can work out the circumference at that point. This is the length of arc for the sector....

i think i need to use θ/360 x d x pi or θ/360 x r2 x pi?

but i don't know how exactly to get there, im so confused :confused:

Reply 5

Original post by ombtom

Second question: height of cylinder = 6*2.7 = 16.2cm. Volume of cylinder = pi*r^2*h. :smile:

oh yeah! that makes perfect sense. I don't even know what i was doing to be honest. Thank you :biggrin:

Reply 6

Beamer786G-Star

Original post by Appazap

oh yeah! that makes perfect sense. I don't even know what i was doing to be honest. Thank you :biggrin:

I would rep him if i was u

Reply 7

Original post by Beamer786G-Star

I would rep him if i was u

oops good idea :colondollar:

Reply 8

Original post by Appazap

i think i need to use θ/360 x d x pi or θ/360 x r2 x pi?

but i don't know how exactly to get there, im so confused :confused:

Look at the cross section. The diameter of the circle at the top of the wrapper is given. What's its circumference?

Reply 9

did u get the answer for the first one??

Reply 10

Original post by ghostwalker

Look at the cross section. The diameter of the circle at the top of the wrapper is given. What's its circumference?

so do you just do 5.6 x pi and that'll give you the circumference?

Reply 11

trust mee, there isn't even a lesson for this

Reply 12

Original post by User23

so do you just do 5.6 x pi and that'll give you the circumference?

yeah thats what i thought and then you've found the curved bit right?

Reply 13

Original post by User23

so do you just do 5.6 x pi and that'll give you the circumference?

Yes. And that's the length of the arc of the sector.

Reply 14

Original post by Appazap

yeah thats what i thought and then you've found the curved bit right?

So you use that arc length as ghostwalker told us. So it would be 5.6 x pi= 17.5929. then i did 12*pi*x/360= 17.5929 and so i found x to be 168, a nice number :tongue:

Reply 15

Original post by User23

So you use that arc length as ghostwalker told us. So it would be 5.6 x pi= 17.5929. then i did 12*pi*x/360= 17.5929 and so i found x to be 168, a nice number :tongue:

oh yeah that makes sense now! Thank you and ghostwalker for helping me with this question, i really appreciate it :smile:

Reply 16

Original post by Appazap

oh yeah that makes sense now! Thank you and ghostwalker for helping me with this question, i really appreciate it :smile:

You're very welcome xx

Reply 17

Original post by User23

So you use that arc length as ghostwalker told us. So it would be 5.6 x pi= 17.5929. then i did 12*pi*x/360= 17.5929 and so i found x to be 168, a nice number :tongue:

Why that formula (in bold)?

If x is in degrees, then converting to radians is x*pi/180

Reply 18

Original post by ghostwalker

Why that formula (in bold)?

If x is in degrees, then converting to radians is x*pi/180

Radians?
All I did was just do x/360 x 12 pi = 14.5929....
Then I made x the subject of the formula

Reply 19