# Math Help - coordinate geometry triangle

1. ## coordinate geometry triangle

2. The points A(-4,10) B(-1,1) and C(2,7) form a triangle

(a) is this a right angle triangle?

(b) what is the length of the triangles perimeter?

any help appreciated

2. Originally Posted by decoy808
2. The points A(-4,10) B(-1,1) and C(2,7) form a triangle

(a) is this a right angle triangle?

(b) what is the length of the triangles perimeter?

any help appreciated
1. Calculate the lengthes of the sides of the triangle using the distance formula.

2. Check if the Pythagorean theorem is satisfied by the lengthes of the sides.
Spoiler:
I've got: $|\overline{AB}|=\sqrt{90}$, $|\overline{AC}|=\sqrt{45}$, $|\overline{BC}|=\sqrt{45}$
Obviously $(\overline{AB})^2 = (\overline{AC})^2 + (\overline{BC})^2$
and therefore the triangle is a right triangle.