Help with math question! (1 Viewer)

[Foxyq]

1. A circle has a chord of 25mm with an angle subtended of pi/3 at the centre. Find, to 1 decimal place, the length of the arc but off by the chord. The answer is 25.3mm.

How do you get the answer? :S

Also,

2. A sector with radius 5cm and an angle of pi/3 subtended at the centre is cut out of cardboard. It is then curved around to form a cone. Find its exact surface area and volume. Answer is SA = 175pi/35 sqr.cm. V= 125 sqaureroot of 35pi/648 sqr.cm

Thank you!

 

[Drongoski]

Q1 - Have u provided all the data?

 

[Foxyq]

Oh sorry, I forgot to provide the angle, it's there now, edited it

 

[Helvetica]

Q1 - Have u provided all the data?

Length of arc =
Can we find r from the chord? hmmm... no.

 

[Helvetica]

Oh sorry, I forgot to provide the angle, it's there now, edited it

find r and use the equation.

 

[Foxyq]

How do you find r?

 

[Drongoski]

Then Q1 is dead easy.

2 x rsin(pi/6) = 2 x r x 0.5 = r = 25 mm

.: arc length = r x (pi/3) = 25 x pi/3 mm

 

[Helvetica]

Then Q1 is dead easy.

2 x rsin(pi/6) = 2 x r x 0.5 = r = 25 mm

.: arc length = r x (pi/3) = 25 x pi/3 mm

There is a forum called the physics forum and if you give the solution to a homework question on that forum you receive an infraction You can only give hints haha

 

[Drongoski]

Really? I'm terribly sorry.

 

[Carrotsticks]

There is a forum called the physics forum and if you give the solution to a homework question on that forum you receive an infraction You can only give hints haha

This is not true, and has no relevance to the current thread.

 

[RealiseNothing]

This is not true, and has no relevance to the current thread.

This.

Who cares what another site supposedly does?

 

[Helvetica]

ok, sorry