SAT Question 23c5fcce: Circles answer and explanation with Desmos solution

Choice B is incorrect. The perpendicular diameters divide the circumference of the circle into four equal arcs; therefore, minor arc $\widehat{AC}$ is $\frac{1}{4}$ of the circumference. However, the length in choice B is $\frac{1}{3}$ the circumference of the circle. This is not $\frac{1}{4}$ the circumference.

Choice C is incorrect. The perpendicular diameters divide the circumference of the circle into four equal arcs; therefore, minor arc $\widehat{AC}$ is $\frac{1}{4}$ of the circumference. However, the length in choice C is $\frac{1}{2}$ the circumference of the circle. This is not $\frac{1}{4}$ the circumference.

Choice D is incorrect. The perpendicular diameters divide the circumference of the circle into four equal arcs; therefore, minor arc $\widehat{AC}$ is $\frac{1}{4}$ of the circumference. However, the length in choice D is the length of the entire circumference. This is not $\frac{1}{4}$ the circumference.