Shifting a circle results to changes in the coordinates of the circle. For instance, if the coordinates of the center of the circle is taken to be (0,0), the new coordinates will be [(0+5),(0+2)] after shifting. The equation of the circle will also change with the same margin.
That is, the new equation will be;
(5+x)^2+(2+y)^2 =19
Notice, only the coordinates changes.
The second one I beileve is the answer to your question
Given:
No of users in February is 45,000 and in october its 60,000.

t=2




Therefore, approximate no of users after 2 years is 106667.
A right angle is an angle with a measure of 90 degrees.