The base of a solid is a region in the first quadrant bounded by the x-axis, y-axis, a the line x + 2y = 8, as shown in the figure above. If cross sections of the solid
perpendicular to the x-axis are semicircles, what is the volume of the solid? Be sure
to round your answers to 3 places past the decimal.

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?