a)
Because the sum of angles in a triangle must equal 180° we can say:
62+α+90=180
α+152=180
α=28°
b)
Since all sides have equal length, all angles must have equal measure. (This is an equilateral triangle). And again, because the sum of the angle must be 180° we can say:
b+b+b=180
3b=180
b=60°
