Respuesta :

Answer:

a = 12cm

Third option

Step-by-step 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.