Which one should I use

Pythagorean Theorem and Sine

Step-by-step explanation:

you could use pythagorean theorem to find the 3rd side, then use inverse sine of c.

Using the equation a2 + b2 = c2

Subtract 13squared from 5squared

169-25

then take the square root of the answer- which is 12

then do the inverse of sine

that should give you the missing angle

the answer is Multiplication Property of Equality