Answer:

Explanation:
Please refer to attached for labeling of the diagram:
We have 2 triangles here in the figure:
 .
.
1. 
 is common to both the triangles.
 is common to both the triangles.
Sides AC || DE (parallel sides): 
So, Corresponding angles will be equal
2. 

3. 

So, 
 are similar to each other.
 are similar to each other.
Similar triangles have ratio of their sides as equal.
So, 


Hence, 
