Answer:
The wide of river is 
Step-by-step explanation:
In this problem we know that
Triangles DEG and DEF are congruent by ASA (Angle-Side-Angle) Congruence
therefore
EG=EF

There are two ways to approach this.
Option #1:
Use the slope formula
.

That value is undefined, so the slope is undefined.
Option #2:
Because the two points have the same x-value, they will be vertically above/below one another. This means your line is a vertical line and the slope of a vertical line is undefined.
Either way, your slope is undefined.
Answer:

Step-by-step explanation:
Coordinates of B are

Coordinates of C are

Distance between two points

Distance of BC




