Answer:
75
Step-by-step explanation:
(1 + x) (13) = 13+6.5
13x + 13 = 19.5
13x = 6.5
x = 0.5
The item was marked up by 50%
C
It is an obtuse triangle and in an obtuse triangle, the circumcenter is ALWAYS outside of the triangle.
Source: https://www.1728.org/trictr.htm
