Question 1208850
Doing the algebra steps should give {{{pi*r^2+pi*r-2=0}}}.


Using quadratic formula solution and taking the positive number will give
{{{r=(-pi+sqrt(pi^2+8pi))/(2pi)}}}


Calculator will then give your result for r.
Use whatever approximation for {{{pi}}} that you want or need.


{{{(-3.14159+sqrt(3.14159^2+8*3.14159))/(2*3.14159)}}}


{{{0.442}}}