standard_description: Know the formulas for the area and circumference of a circle and use them to solve problems; give an informal derivation of the relationship between the circumference and area of a circle.
problem_activity: Line
$$AC$$
intersects line
$$EB$$
at point
$$F$$
. Ray
$$FD$$
extends from point
$$F$$
. Determine the measures of
$$\angle EFD$$
and
$$\angle CFD$$
.
[IMG]


aligns: no