Which expression can be used to form an identity with 1 over cos squared theta minus 1

Which math sentence can be used to determine if the triangle is a right triangle?

The following frequency table relates the weekly sales of bicycles at a given store over a 42-week period. value01234567frequency367108521(a) in how many weeks were at least 2 bikes sold? (b) in how many weeks were at least 5 bikes sold? (c) in how many weeks were an even number of bikes sold?

A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2