Sector question

[jess5085]

Hello,
I'm stuck on part (c) of this question. How would I find the theta?


My working out so far:


Thanks in advance!

 

[stapel]

Hello,
I'm stuck on part (c) of this question. How would I find the theta?
View attachment 4968

My working out so far:
View attachment 4969

Thanks in advance!

a) Other than some messiness (the "-c" in the third line should be "=c²", I'm pretty sure the "\(\displaystyle =11\cdot66\)" is supposed to be "\(\displaystyle \approx 11.66\)", etc), the computations here are correct.

b) Yes, this value will be the same as that in (a).

c) What is the radius of the base of the cone? Then what is the circumference of the base of the cone? Given the value of r, what was the circumference of the circle of paper, before it was formed into a cone? What then is the arc-length of the portion that was cut out?

d) You have the radius value and the arc length, and you have the arc-length formula in terms of radius and angle. What then is the angle?

If you get stuck, please show your work so far. Thank you!