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### Course: Digital SAT Math>Unit 13

Lesson 2: Congruence, similarity, and angle relationships: advanced

# Congruence and similarity — Basic example

Watch Sal work through a basic congruence and similarity problem.

## Want to join the conversation?

• Really difficult way, If we know that the triangles are similar we could,
Divide DE by BA =x..and then we Multiply X by BC
Like this...
7.5/2.5 = 3
3 multiply 2.1=6.3= CE
• that's what I did as soon as I saw the problem and then as he was solving it I was like whaaat why is he making this so hard
• the part where sal said "if some these sound like greek to you but you are not greek"😂😂😂😂
• An Indian student will solve something like this, as ABC ~ DEC, Now we can use corresponding parts to write something like this :-

AB/DE = BC/EC = AC/DC

Now we need only EC or CEO, and we are given with AB, DE and BC, so we will take `AB/DE = BC/EC` and put the values in like

2.5/7.5 = 2.1/CE and now do your calculation by cross multiplying and wohhoo, u have your answer :)
• So if I knew about transversals and parallel lines before this video I am greek? nice
• har har hr har har har hr har har harrrr
• i need to pass my sat :(
• look up Thales theorem if you want an easier explanation for this
• there ain't no diagram at left.
(1 vote)
• True! With the double negative, you are saying that there is in fact a diagram at the left ;)