So, here you have 90° angles – 90°angles – 90° angle – that is cut in half. Then it is
going to be a 45° angle. And we know that a triangle has to have - so this will be 45
here. And so 45 here and 45 here. So 90 – 90. If they have the same – if this, a equals
the length, let’s call it one, this is one, okay? If this equals the length of that – you
know, two and two, then it’s gotta be the same.