Question

What is the perimeter of the polygon defined by the points A(12, 20), B(20, 20), C(20, 8), and D(12, 8)? a 64 units b 144 units c 84 units d 40 units

Answer 1

d. 40 units

Explanation:

The length of the horizontal side of this rectangle on the line y=20 is the difference of the x-coordinates, 12 and 20, so is 8. The length of the vertical side on the line x=20 is the difference of the y-coordinates, 20 and 8, so is 12.

Two sides are of length 8 and two are of length 12. The perimeter is the sum of the side lengths, so is ...

P = 2·8 +2·12 = 40 . . . units