I assume each path
is oriented positively/counterclockwise.
(a) Parameterize
by

with
. Then the line element is

and the integral reduces to

The integrand is symmetric about
, so

Substitute
and
. Then we get

(b) Parameterize
by

with
. Then

and

Integrate by parts with



(c) Parameterize
by

with
. Then

and

The integers are x - 1, x and x + 1
x - 1 + x + x + 1 = 186
3x = 186
x = 186/3 = 62
Therefore, the numbers are 61, 62 and 63
Use the equation (x2-x1)/(y2-y1)
Substitute the value of x and y