Explanation:
with reference angle theta
perpendicular (p) = 8
base (b) = 15
hypotenuse (h) = ?
We know by using Pythagoras theorem
h² = p² + b²
h² = 8² + 15²
h² = 64 + 225
h² = 289
h = √289
h = 17
Therefore the missing side is 17.
Now
sin theta = p / h = 8 / 17
cos theta = b / h = 15/17
tan theta = p / b = 8 / 15
Hope this helps.!