To the nearest tenth, find the perimeter of ∆abc with vertices a(2,4), b(-2,1) and c(2,1).

If you plot the triangle on a graph, you'll see that the shape is a right triangle. Using the distance formula we can calculate the distance between point A and point B, which is the hypotenuse. 

√(2− (−2))^2 + (4−1)^2
√(2+2)^2 + (4−1)^2
√(4)^2 + (3)^2
√6+9
√25
= 5

5 + 6 + 8 = 19. The perimeter of triangle ABC is 19 units. Hope this helps:)

~Ash