Answer:
I might be in highschool, but I'm sure I can still help.
Explanation:
See the 45 degree angles? that means they're equal sides. So 4v2 = 5.65, right? so if you take 180 - 5.65, and then divide by two, you should have the length to each of those sides. They're equal, remember. So, the answer would be 180 - 5.65 = 174.35. 174.35 / 2 = 87.175. In this case, k = 87.175 :)