Using the Pythagorean theorem:
c = sqrt(8^2 + 7^2)
c = sqrt(64 + 49)
c = sqrt(113)
c = 10.6
Given:

First, let us find two points from this equation.
We can set values of x and then solve for y.
Let us find the values of y when x = 1, 2, 3, 4, 5

We now have a set of points:
(1, 21)
(2, 16)
(3, 11)
(4, 6)
(5, 1)
Since the given plane is limited to values of 10 and -10, the points that we can plot are the points (4, 6) and (5, 1)
The graph would then look like this:
Answer:
The next term in the sequence can be determined by subtracting 1.5 from 3.9 which is 2.4 and then you test it and say 3.9 plus 2.4 is 6.3 then plus 2.4 is 8.7 then the next term would be 11.11