the correct question is
The hypotenuse and one of the legs of a right triangle form an angle that has a cosine of √2/2 .
What is the measure of the angle?
Let
∅--------> the angle
cos ∅=√2/2
cos ∅=[distance of one of the leg/hypotenuse]
[distance of one of the leg/hypotenuse]=√2/2
I could say that
distance of one of the leg=√2
and
hypotenuse=2
so
applying the Pythagorean theorem
c=hypotenuse=2
a=√2
b=?
c²=a²+b²-------> b²=c²-a²------> b²=2²-(√2)²-----> b²=2-----> b=√2
therefore
if a=b
then
the angle ∅=45°
the answer is the option
b.45 degrees