Would this be 90? with steps please ​

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

Which equation expression the relationship between the number of boxes b and the number of cans c and the proportion is 48