Circumference C, radius r.
[tex]C = 2\pi r[/tex]
[tex]r = \dfrac{C}{2\pi}[/tex]
[tex]\pi r^2 = \pi \dfrac{C^2}{4 \pi^2} = \dfrac{C^2}{4\pi}[/tex]
75% of the area is
[tex]\dfrac{3}{4} \pi r^2 = \dfrac{3C^2}{16\pi}[/tex]
Plugging in C=10 gives
[tex]\dfrac{3}{4} \pi r^2 = \dfrac{3(10)^2}{16\pi} = \dfrac{75}{4 \pi} \approx 5.97[/tex]
Choice 1, 6 square units.
