Find a positive angle less than 2pi that is coterminal with 28pi/9

Write the following as a base and exponent

Satchi found a used bookstore that sells pre-owned dvds and cds. dvds cost $9 each, and cds cost $7 each. satchi can spend no more than $45.

Given sin∅ = 1/3 and 0 < ∅ < π/2 ; find tan2∅ a. (4√2)/9 b. 9/7 c. (4√2)/7 d.7/9