Question

The coordinates of the vertices of a polygon are (−2,1), (−3,3), (−1,5), (2,4), and (2,1).

What is the perimeter of the polygon to the nearest tenth of a unit?



15.2 units

15.9 units

16. 5 units

18.8 units

Answer 1

`√(5) + 2 √(2) + √(10) + 3 + 4 \\ = 2.24 + 2.83 + 3.16 + 3 + 4 \\ = 8.23 + 7 = 15.23`
So the best rounded answer to nearest tenth is: A) 15.2 units

Answer 2

Name them as vertices A,B,C , D and E in that order.


`ab = \sqrt{ {( - 2 + 3)}^(2) + (1 - 3)^(2)} = √(5) \\ bc = \sqrt{ {( - 3 + 1)}^(2) + {(3 - 5)}^(2) } = 2 √(2) \\ cd = \sqrt{ { (- 1 - 2)}^(2) + {(5 - 4)}^(2) } = √(10) \\ de = \sqrt{ {(2 - 2)}^(2) + {(4 - 1)}^(2) } = 3 \\ ea = \sqrt{ {(2 + 2)}^(2) + {(1 - 1)}^(2) } = 4 \\ peimeter = ab + bc + cd + de + ea = 15.227 \: or \: 15.23`