SOH,CAH, TOA so it would be TANGENT since it would be Opposite over Adjacent. Tan(15) = 9/a put Tan(15) onto your calculator it would be .267949 round that to .27 = 9/a cross multiply
a = 33.588. C is the correct answer.
Hi. The statement you gave is somewhat true, but not always. I disprove this and there are tons of websites that can help you with more in depth explanation. Have a good day.