Question 1100429
Calculate the semi-minor length using,
{{{c^2=b^2-a^2}}}
{{{c=(11-7)/2=4/2=2}}}
{{{2^2=9^2-a^2}}}
{{{a^2=81-4}}}
{{{a^2=77}}}
{{{(x-4)^2/77+(y-9)^2/81=1}}}