Question

What is the perimeter of a polygon abcd vertex a(5,12) b(9,9) c(12,5) d(0,0)

a.28 units
b.32 units
c.36 units
d.44 units

Answer 1

c. 36

Explanation:

that is what that one says up there

Answer 2

36

Explanation:

We have to compute 4 distances and then add them up.

It may help to draw this first to see which distances to compute.

So I'm going to start with computing the distance from (0,0) to (5,12), then from (5,12) to (9,9), then from (9,9) to (12,5), and then finally from (12,5) to (0,0).

So distance from (0,0) to (5,12)

d=sqrt((5-0)^2+(12-0)^2)=sqrt(25+144)=sqrt(169)=13

Distance from (5,12) to (9,9)

d=sqrt((9-5)^2+(12-9)^2)=sqrt(4^2+3^2)=sqrt(16+9)=sqrt(25)=5

Distance from (9,9) to (12,5)

d=sqrt((12-9)^2+(9-5)^2)=sqrt(3^2+4^2)=sqrt(9+16)=sqrt(25)=5

Distance from (12,5) to (0,0)

d=sqrt((12-0)^2+(5-0)^2)=sqrt(12^2+5^2)=sqrt(144+25)=sqrt(169)=13.

Up all of our distances 13+5+5+13=(13+13)+(5+5)=26+10=36