The midpoint of GN is (9, 11). One endpoint is N(7,5). Your friend calculates the coordinates of endpoint G as (15, 13). What is his error?
A. He switched the x and y coordinate in the Midpoint Formula.
B. He use the midpoint as one of the endpoint
C. His calculations using the Midpoint Formula were not simplified correctly
D. He found the midpoint between N and the midpoint of GN
