Help plz! Chords, secant segments and tangents are shown. Write an equation, then find the variable(s).

An explanation on how to solve would be great!

Three coins are flipped. what is the probability that there will be at least two tails?

Asmall business produces and sells balls. the fixed costs are $20 and each ball costs $4.32 to produce. each ball sells for $8.32. write the equations for the total cost, c, and the revenue, r, then use the graphing method to determine how many balls must be sold to break even.

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.