Question

Tracy is finding the equation of a median-median line. She found that the equation of the line through the first and third summary points is y = 0.4x + 38. Then she found that the equation of the line that is parallel to this line and passes through the second summary point is y = 0.4x + 59. What is the equation of the median-median line?. . a. y = 0.4x + 41. . b. y = 0.4x + 45. . c. y = 0.4x + 52. . d. y = 0.4x + 56.

Answer 1

1) Find the equation of the line that passes through (x1, y1) and (x3, y3).
We have it: y = 0.4x + 382) Find the equation of the line parallel to the previous line that passes through (x2, y2). 
That is: y = 0.4x + 59
3) Find the weighted average of the
y-intercepts.  b=(b1+b2+b1)/3 = (38+59+38)/3
                      b= 45
The median-median line is the line parallel to the previous two lines with the weighted y-intercept.Hence, Y = 0.4 x + 45 is the answer