What is the radius and diameter of the following circle?

What point is the projection of q on a) r b) s c) t

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

What percent of 18 is 24? and plz explain thx.