What is the ratio ABBC for the line segment AB following the construction method below?
Step 1. A ray is extended from A and 30 arcs of equal lengths are cut, cutting the ray at A1,A2,...,A30
Step 2. A line is drawn from A30 to B and a line parallel to A30B is drawn, passing through the point A17.
17:13
Here the total number of arcs is equal to m+n in the ratio m:n.
The triangles △ AA17C and △ AA30B are similar.
Hence, ACAB = AA17AA30 = 1730
1 = AB/AB = ACAB + BCAB
BCAB = 1 - 1730 = 1330
Hence, ABBC = 1713 = 17:13.