Answer: second option
Explanation:
You know that it is a right triangular window frame.
Then, you can use the Pythagoren Theorem to find the lenght of the third side:
Where "a" is the hypotenuse (or the longest side), and "b" and "c" are the legs .
Then, you can solve for one of the legs:
Since you know the lenght of the hypotenuse and the lenght of one leg, you can substitute values.
Therefore, you get: