Question

What is the perimeter of the triangle shown on the coordinate plane, to the nearest tenth of a unit?

19.2 units

22.3 units

27.4 units

36.0 units

Answer 1

A(-4,-1), B(-1,7), C(6,3)

`AB = √((-1 - -4)^2 + (7--1)^2)=√(3^2+8^2)=√(73)`

`BC = √((6 - -1)^2+(7-3)^2)=√(49+16)=√(65)`

`AC=√((6 - -4)^2+(3--1)^2) = √(116)= 2 √(29)`

`\textrm{perimeter} = √(73) + √(65) + 2 √(29) = 27.3766...`

Answer: 27.4