I REALLY need help... PLZ

If ac = 12 and ab=7 is it possible that bc =10

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?

Find the area of the region that is inside r=3cos(theta) and outside r=2-cos(theta). sketch the curves.