Question

Triangles ABC and DEF are similar. If DE = 9, EF = 7, and AB = 4.5, what is BC?

Answer 1

`BC=3.5`

Explanation:

If two given triangles are similar i.e. `DeltaABC~Delta DEF`. then

`/_A=/_D`, `/_B=/_E`, `/_C=/_F` and `(AB)/(DE)=(BC)/(EF)=(CA)/(FD)`

As `DE = 9`, `EF = 7`, and `AB = 4.5`, we have

`4.5/9=(BC)/7` and

`BC=7xx4.5/9=7/2=3.5`