Answer: Hope This Helps!
Explanation:
Use the distance formula to calculate the side length of each side of the triangle. If any 2 sides have equal side lengths, then the triangle is isosceles.
More precise info: Given the coordinates of the triangle's vertices, to prove that a triangle is an isosceles plot the 3 points (optional) use the distance formula to calculate the side length of each side of the triangle. If any 2 sides have equal side lengths, then the triangle is isosceles.