Sam has 21 books in his library. He bought several books at a yard sale over the weekend. He now has 78 books in his library. How many books did he buy at the yard sale? S.
89
ООО
57
75

Aprism and two nets are shown below: image of a right triangular prism and 2 nets. the triangle bases have base 4, height 3, and diagonal side 5. the length of the prism from the bases is 9.4. net a has 3 rectangles in a row. the middle one has sides ac and cd. this middle one has triangle abc on top and identical triangle below. net b is the same except that the triangle base abc is on top of the last rectangle which has sides ac and cd. units are in inches. part a: which is the correct net for the prism? explain your answer. (2 points) part b: write the measurements of sides ab, bc, and cd of the correct net. (4 points) part c: what is the surface area of the prism? show your work. (4 points)