Ok, I have some questions, these are all using radians

Question 1

Convert the following angles to radians giving your answers correct to 3SF.

a) 20 degrees

b) -72 degrees

c) 400 degrees

d) -140 degrees

e) 760 degrees

Question 2

An angle "p" subtends an arc of length 25cm in a circle of radius R cm.

The area of the sector POQ is 72cm (squared)

Forumulate two equations in r and "p" Find the values of r and "p"

Question 3

A cylindrical pipe of diameter 1.5m contains water to a depth of 0.9m.

a) find the cross sectional area of the water

b) if the water is flowing at a rate of 60 litres per second fin dthe speed of the water in m/s

I would really appreciate any help offered, these are the final pieces of some homework and i really need help, thank you