Answer:
A. 5
Step-by-step explanation:
The triangle given is a right triangle. To solve for y, apply the pythagorean theorem which is given as a² + b² = c².
Where,
c is the hypotenuse/longest side = 13
a = 12
b = y
Plug in the values
12² + y² = 13²
144 + y² = 169
y² = 169 - 144
y² = 25
Square both sides
y = √25
y = 5