Two trees stand opposite one another. At points A and B. On opposite banks of a river. Distance AC along one bank is perpendicular to BA is measured to be 61. How far apart are the trees that is, what is the width w of the river?

Jack has a rectangular piece of land, the area of which is represented by a1 = 9.5l. his brother has a different rectangular piece of land, the area of which is represented by a2 = l(14 − l). let a represent the area in square meters and l represent the length in meters of the pieces of land. the two equations plotted on a graph meet at a point as shown in the image