Oh, this is easy love :)
So, b is the length of the side opposite angle B and c is the length of the side opposite angle C and h is the length of the hypotenuse.
sin(B) = b/h and cos(B) = c/h
sin(B) = cos(B) means b/h = c/h which gives c = b
The two sides are equal in length which means that the triangle is isosceles and angles B and C are equal in size of 45 degrees!
I hope this helps!
