A chalkboard has a perimeter of 18 ft and is 6 ft long. Find the height of the chalkboard

P = 2H + 2L

L = 6

P = 18

18 = 2H + 2*6

18 = 2H + 12

6 = 2H

H = 3 ft

The height of the chalkboard is 3ft. Since the chalkboard has a perimeter of 18ft, that means that the 2 lengths of the board are 6 ft or 12 ft added together. Afterwards, subtract 12 from 18 ft (18 - 12), which shall get you 6ft. Then, divide 6 by 2, since there are two sides that represent the height.

Therefore, the height is 3 ft.