Question

What's sec?!

Answer 1

Sec is just the reciprocal of cos
to find cos use adjacent/hypotenuse
so that's 9/15
get the reciprocal. 15/9
then simplify .5/3

Answer 2

Thank you! Can you tell me what csc is too? :]

Answer 3

its the reciprocal of sine.

Answer 4

Yup.Just get sin opposite/hypotenuse
12/15
then get its reciprocal 15/12
simplify 5/4

Answer 5

Thanks!! :D

Answer 6

Kahn Academy has a great intro to trigonometric identites and the unit circle.
Probably the best 7 minutes I have spent listening to someone talk about trig.