When constructing an equilateral triangle, what step comes after six arcs are created on the circle? Connect every other intersection of an arc and the circle with a segment.
Connect the intersections of the diameters and the circle with a segment.
Connect every intersection of an arc and the circle with a segment.
Connect the intersections of the perpendicular bisector and the circle with a segment.

graph them on a graphing calculator, press 2nd trace. select intersect. hit enter until it says answer. ti 84 works best

step-by-step explanation:

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

a≈380.13mi² would be your answer if the radius was 11 miles