BC¯¯¯¯¯ is parallel to DE¯¯¯¯¯. What is AB? Geometry Similarity Triangle Similarity 1 Answer CW Feb 4, 2017 #AB=34# Explanation: Given #BC# is parallel to #DE# : Construct line segment #BF# parallel to #CE#, #=> BF=CE=21#, as shown in the diagram. #=> DeltaBDF, DeltaABC and DeltaADE# are similar. #=> (AB)/(AC)=(BD)/(BF)# #=> (AB)/42=17/21# #=> AB=(42xx17)/21=34# Answer link Related questions If I have two triangles, and they are similar but different sizes, how would I write a... Are all equilateral triangles similar? Explain your answer please? What is the relationship between corresponding sides, altitudes, and medians in similar triangles? What are the applications of similar triangles in real life? Triangle A has sides of lengths #7 ,4 #, and #8 #. Triangle B is similar to triangle A and... Triangle A has sides of lengths #7 ,4 #, and #5 #. Triangle B is similar to triangle A and... Triangle A has sides of lengths #1 ,4 #, and #5 #. Triangle B is similar to triangle A and... Triangle A has sides of lengths #1 ,4 #, and #4 #. Triangle B is similar to triangle A and... Triangle A has sides of lengths #1 ,3 #, and #4 #. Triangle B is similar to triangle A and... Triangle A has sides of lengths #8 ,3 #, and #4 #. Triangle B is similar to triangle A and... See all questions in Triangle Similarity Impact of this question 9436 views around the world You can reuse this answer Creative Commons License