If ?ABE is similar to ?ACD by the SAS similarity theorem, AD must equal how many units.

Answer: 24 units
Step-by-step explanation:
Given: Δ ABE is similar to Δ ACD by the SAS similarity theorem.
Since the corresponding sides of similar triangles are proportional.
Therefore we have
[tex]\frac{AB}{AC}=\frac{AE}{AD}\\\\\Rightarrow\frac{AB}{AB+BC}=\frac{AE}{AE+ED}\\\\\Rightarrow\frac{6}{6+30}=\frac{4}{AD}\\\\\Rightarrow\ AD=\frac{4\times36}{6}\\\\\Rightarrow\ AD=24[/tex]
Hence, if Δ ABE is similar to Δ ACD by the SAS similarity theorem then AD must equal 24 units.