28.3
Explanation:
imagine it's a complete circle, and find its are
pi × r^2
which is 36pi (keep ur answer in pi for now)
because it's a quarter of a circle ( 1/4) we decide the are of the full circle by 4 to get the quarter's area
36pi ÷4 = 28.27433388 which is about 28.3 ( as u see we kept it in pi for a more accurate number)