Draw two different shapes with an area of 16 square units. what is the perimeter of each shape?

-- Rectangle, 1 unit wide, 16 units long
Area = 1 x 16 = 16 square units. 
Perimeter = (1 + 16 + 1 + 16) = 34 units.

-- Rectangle, 2 units wide, 8 units long
Area = 2 x 8 = 16 square units. 
Perimeter = (2 + 8 + 2 + 8) = 20 units.

-- Square, 4 units on each side
Area = 4 x 4 = 16 square units. 
Perimeter = (4 + 4 + 4 + 4) = 16 units.

-- Circle, Diameter = 4.515 units
Area = π R² = π (4.515/2)² = π (2.2575)² = 16 square units
Perimeter = circumference = π (diameter) = 4.515 π = 14.18 units

It would have infinite solutions.