The equation for the area of a circle is:

. Insert 9 as your radius (r) into the equation and solve:
\pi 9^2 = 254.469
To best emphasize the number of defects. Manager should use graph 3 (refer the image shown):
If we talk about graph 1, it can also be used but usually we put the time line on the horizontal axis, for the convenience and the quantity to be measured on the y-axis. In the graph 1, the time is placed on the vertical axis (x-axis) so it would not be a good pick for the manager.
Same is the case with graph 2 again we have time on the vertical axis. So it is not a good idea to with graph 2.
Graph 3 could be the best to emphasize the number of defects because first of all time is placed on the horizontal axis and the quantity to be shown is on the vertical axis. Secondly, the range of the vertical axis is less so it is easy to observe the data set on the graph quite distinctively. Therefore, graph 3 is the best pick.
Graph 4 is placed correctly in terms of vertical and horizontal axes but the range of vertical axis is quite high due to which the dispersion or the display of the data is quite compressed and it gets hard to visualize.
After 20 months. after 20 months the first dealer will cost 5500 and the second dealer will cost 5500
dealer one pays 3000 in monthly fines and 2500 down and dealer 2 pays 2500 in fines and 300 down
Assuming your numbers are rounded to the nearest km, the minimum area will be ...
(5.5 km)·(10.5 km) = 57.75 km² . . . minimum
And the maximum area will be ...
(6.5 km)·(11.5 km) = 74.75 km² . . . maximum
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When a number is rounded to 6 km as the nearest km, its value may actually be anywhere in the range 6 km ± 0.5 km. If you really want to get technical about it, the ranges of possible dimensions are [5.5, 6.5) km and [10.5, 11.5) km, and the range of possible areas is [57.75, 74.75) km².