Answer: second option
Step-by-step 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:
[tex]a^2=b^2+c^2[/tex]
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:
[tex]b^2=a^2-c^2\\b=\sqrt{a^2-c^2}[/tex]
Since you know the lenght of the hypotenuse and the lenght of one leg, you can substitute values.
Therefore, you get:
[tex]b=\sqrt{(87in)2^-(63in)^2}\\b= 60in[/tex]
