Answer: Use the distance formula to see if at least two sides are congruent.
Step-by-step explanation:
We know that an isosceles triangle is a triangle whose atleast two sides are congruent.
So if we need to prove a triangle is isosceles then we need to prove that its atleast two sides are congruent. or equal.
Therefore, we can use the first method to prove the triangle is isosceles.
"Use the distance formula to see if at least two sides are congruent.
