A straight line is drawn through point B of side PK of triangle KTP, parallel to side TK and intersecting side PT at point

A straight line is drawn through point B of side PK of triangle KTP, parallel to side TK and intersecting side PT at point A. Calculate the length of the segment AB if KT = 52cm, AT = 12cm, AP = 36cm.

Because the line AB is drawn in the triangle KTP, parallel to the base of TK, hence the triangles KTP and BAP are similar.
PT = AT + PA = 48
Similarity factor = AP / PT = 3/4
AB / TK = 3/4
AB / 52 = 3/4
4AB = 3 * 52
AB = 39
Answer: 39 cm