help with this I don't know how to solve plz greatly appreciate

Answer:
cos∅ = 16√481/481
Step-by-step explanation:
Pythagorean Theorem: a² + b² = c²
cos∅ = adjacent/hypotenuse
tan∅ = opposite/adjacent
Step 1: Find hypotenuse
15² + 16² = c²
c = √481
Step 2: Find cos∅
cos∅ = 16/√481
cos∅ = 16√481/481