Find the indicated length

Find DE

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

A.s.a.! this is a similarity in right triangles. next (solve for x)a.) 12b.) 5c.) 12.5d.) [tex] 6\sqrt{3} [/tex]

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25