If ground level is zero in the first level above ground is one which integer can use to represent the other levels where objects are head and explain your reason

Alakefront cottage that is 30 feet high casts a shadow on the water. how long is that shadow if a 16-foot-high truck parked nearby casts an 8-foot shadow?

Right triangle lmn has vertices l(7, –3), m(7, –8), and n(10, –8). the triangle is translated on the coordinate plane so the coordinates of l’ are (–1, 8). (x, y) → (x + 6, y – 5) (x, y) → (x – 6, y + 5) (x, y) → (x + 8, y – 11) (x, y) → (x – 8, y + 11)

Ihave 9 cowry shells if a dozen eggs(12 eggs) cost 2 cowry shells how many dozens can i purchase