Answer:
20 inches
Step-by-step explanation:
When the instructions say a triangle is similar, it basically means they are exactly the same unless otherwise specified.
With this, we just need to find the ratio.
We can see that DE is 6 inches while AB is 18 inches.
This means that the ratio between DEC and ABC is 1:3, respectively.
So if AC is 30, that means DC should be 10.
All we have to do now is subtract DC from AC to find AD
30 - 10 = 20
So AD is 20 inches
I'm pretty sure there is a more mathematical approach to this but this is good enough to solve any problem like this.
