fx[t] is normalized over [0,1], but the but fy[t] is normalized over [ 0, Sqrt[3]/2]
In[10]:= Integrate[fx[t], {t, 0, 1}]
Out[10]= 1
In[11]:= Integrate[fy[t], {t, 0, Sqrt[3]/2}]
Out[11]= 1
In[13]:= Integrate[fx[t], {t, 0, Sqrt[3]/2}] // N
Out[13]= 0.99957