let, the base of the given isosceles triangle be "x"
Now,
If the base is x, then the length of the legs will be [tex]9+ \frac{1}{2}x [/tex]
Now,
Perimeter = sum of all sides
[tex]146 = (9+ \frac{1}{2}x )+(9+ \frac{1}{2}x)+x[/tex]
[tex]146 = 18+x+x[/tex]
[tex]146 - 18 = 2x[/tex]
[tex]128 = 2x[/tex]
[tex] \frac{128}{2} =x[/tex]
[tex]64 =x[/tex]
Now, substitute the value of x in the equation for legs of the triangle,
legs = [tex]9+ \frac{1}{2}x[/tex]
= [tex]9+ \frac{1}{2}(64)[/tex]
= [tex]9+ 32[/tex]
= [tex]41[/tex] inches.
So, the answer to your question is B.