How to find a point dealing with ratios?

Question

1. Point R is located on MN so that it splits the segment into two smaller segments, MR and RM. If the ratio of m MR to mRN is 3:4, what are the coordinates of point R? Explain your answer.

Answer 1

x coordinate of R = x coordinate of M + 3/7 * (x coordinate of N - x coordinate M)

y coordinate of R = y coordinate of M + 3/7 * (y coordinate of N - y coordinate M)