Explanation:
to get a we use cos and for b we use sin
so
cos(45°) =a/5√2....... when u criss cross it
a = cos(45°) × 5√2
a = √2/2 × 5√2
a= 5
sin(45) = b/5√2
b= sin(45) × 5√2
b = 5
In other way if u find the 1st side you r indirectly find the 2nd one which they are equal .