|3.0||95.0||2.1 x 1040
|10.0||110.0||5.6 x 1040
|15.0||110.0||8.4 x 1040
The mass increases as the distance from the center of the galaxy increases. This is because stars move under the gravitational influence of all the matter within their orbit. So stars at greater distances move under the influence of more mass than stars closer to the center.
The best estimate for the mass of the galaxy is the one which includes the most amount of mass. From this calculation, the largest value is 8.4 x 1040 kg. The actual mass of the galaxy is likely to be more than this. From Part 1, we know the mass of the Sun is 2.0 x 1030 kg. So this galaxy is at least 4.2 x 1010 times more massive than the sun.