I need to find the perimeter of three coordinates. They are, A(2,-2) B(-3,4) and C(-3,-2). These points make a triangle so I need to find the perimeter using the triangle formula I’m pretty sure.

Answer 1

Anna,

When you plot the 3 points A, B, and C, you end up with what looks to be a right triangle. A and C are directly horizontal from each other (on the same horizontal line) and they are exactly 5 units apart, so the length of side CA would be 5. Points B and C are directly vertical from each other (on the same vertical line) and they are exactly 6 units apart so the length of side BC would be 6.

Since this is a right triangle and we know the lengths of 2 of the sides, we can use the Pythagorean Theorem to find the length of the 3rd side (AB).

a² + b² = c²

5² + 6² = c²

25 + 36 = c²

61 = c²

c = √61 or approximately 7.81

Calculating the perimeter of a triangle is the same as a square or a rectangle, you just add up the lengths of all of the sides. So, the perimeter of this triangle is 5 + 6 + √61 = 18.81

Answer 2

A and C have the same y coordinate. Distance AC = 5, the difference in x coordinates

B and C have the same x coordinate. Distance BC = 6, the difference in y coordinates

2 sides of the triangle are 5 and 6

Last side is AB d^2 = 61

AB = sqr61

Perimeter= AB + AC + BC= sqr61 + 11 = about 18.9