Simply and solve this equation : 4m+9+5m-12=42

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 net of the rectangular prism, what is its surface area?

Given that the images represent 4 steps in the construction of a line segment congruent to a given line segment, which is step 3 in the construction?