Answer:
Part A) Yes, Kayla can conclude that the triangles ABC and EDC are similar (see the explanation)
Part B) The width of the river is 45 feet
Step-by-step explanation:
<u><em>The correct question is</em></u>
(A) Can Kayla conclude that ΔABC and ΔEDC are similar? Why or why not?
(B) Suppose DE = 21 ft. What can Kayla conclude about the width of the river?
The picture in the attached figure
we know that
If two triangles are similar, then the ratio of its corresponding sides is proportional and its corresponding angles are congruent
Part A) we know that
The <u><em>AA Similarity Theorem</em></u> states: If two angles of one triangle are congruent to two angles of another triangle, then the triangles are similar
In this problem
-----> by vertical angles
-----> is a right angle
therefore
Triangles ABC and EDC are similar by AA Similarity Theorem
Part B) we know that
The triangles ABC and EDC are similar -------> see Part A
so

substitute the given values and solve for AB



therefore
The width of the river is 45 feet