Answer:
65
Step-by-step explanation:
if they are similar their sides are in proportion and so are the corresponding medians
to see their corresponding sides line up the names of the triangles
N Q Z
⇵⇵⇵
C B K
BK / QZ = 45/27 ; substitute whit what you see in the picture
(4x+1) / (2x+7) = 45/27 ; cross multiply
27( 4x+1) = 45( 2x+7) ; distribute
108x + 27 = 90 x + 315; subtract 90x and 27 from both sides
108x -90x = 315 -27; combine like terms
18x = 288; divide both sides by 18
x=16
BK = 4* 16 +1 = 65