Mary thinks the triangle is equilateral. How would you support or dispute her conjecture?Calculate the slope of all three sides, and check whether the slopes are equal.Calculate the slope of all three sides, and check whether any slopes are reciprocals.Use the distance formula to calculate the length of all three sides, and check whether all sides are congruent.Use the distance formula to calculate the length of all three sides, and check whether any two sides are congruent.

Whether it's an isosceles, a scalene, an obtuse or an equilateral triangle proving the type of triangle really has nothing to do with the slope or gradient, so the first two options are out. The essence of calculating is to get the change or derivative. So the first two options are out. An equilateral triangle has all three sides equal. It also has equal congruent sides. Calculating the length using the distance formular or If the perimeter of the triangle is known, calculating one side of the triangle and multiplying by three should tally. If it doesn't then it isn't; but an equilateral triangle should also have equal congruent sides. An isosceles triangle has two congruent side and a scalene has none.