Answer:
a = 12cm
Third option
Explanation:
Use the pythagorean theorem because this is a right triangle and you are looking for a missing side.
The formula is:
a² + b² = c², where "a" and "b" are sides, but "c" is the hypotenuse (longest side).
We know the hypotenuse and one other side.
Substitute side "b" and "c".
a² + 5² = 13²
a² + 25 = 169 Isolate "a"
a² = 169 - 25 Subtract 25 from both sides
a² = 144 Find the square root of both sides
a = √144
a = 12
The mssing side, "a", is 12 cm long.