Fide f (5) evaluate the function

What are the equivalent ratios for 24/2= /3= /5.5=108/ = /15

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?

Tan198=asin164=? how to solve this? ?