Need help doing this workbook, thanks!

Answer: Anwser is 10.5
Step-by-step explanation:
Alright, lets get started.
Given that
[tex]AB=4[/tex]
[tex]AC=6[/tex]
[tex]AD=7[/tex]
Since triangle ABD and triangle ACE are similar triangles, so
[tex]\frac{AB}{AC}=\frac{AD}{AE}[/tex]
[tex]\frac{4}{6} =\frac{7}{AE}[/tex]
Cross multiply
[tex]4 \times AE = 6 \times 7[/tex]
[tex]AE=\frac{42}{4}[/tex]
[tex]AE=10.5[/tex]
Hence the answer is 10.5 .... Answer
Hope it will help :)