This is the concept of geometry; given that the tangent of circle is always perpendicular to the radius, to solve for the measure of the radius will be given by the pythagorean theorem. c^2=a^2+b^2 where;
a=base=radius b=height=hypotenuse c=hypotenuse
substituting the values in our formula we get: 11.7^2=8^2+r^2 r^2=11.7^2-8^2 r^2=136.89-64 r^2=72.89 squaring both sides to get the value of r we get: r=sqrt (72.89) r=8.5376 in
