Solve the Proportion: Finding the Missing Term in AD/_ = AE/AC

BC is parallel to DE.

Fill in the gap:

$\frac{AD}{}=\frac{AE}{AC}$

Since we are given that line BC is parallel to DE

Angle E equals angle C and angle D equals angle B - corresponding angles between parallel lines are equal.

Now let's observe that angle D is opposite to side AE and angle B is opposite to side AC, meaning:

$\frac{AE}{AC}$

Now let's observe that angle E is opposite to side AD and angle C is opposite to side AB, meaning:

$\frac{AD}{AB}$