Question

1. if a perpendicular bisector goes through the vertex of a triangle, the triangle is with out a doubt? scalene isosceles equilateral not a triangle

Explanation:

A perpendicular bisector of a side of a triangle that passes through the opposite vertex implies that the two segments created by the bisector on the side are equal, and by the Perpendicular Bisector Theorem (or properties of triangle congruence), the two adjacent sides to the vertex are equal. A triangle with at least two equal sides is isosceles. A scalene triangle has all sides unequal, an equilateral triangle is a special case of isosceles with all sides equal, but the condition here only guarantees at least two equal sides (hence isosceles). It can't be "NOT a triangle" as the figure is a triangle.

Answer:

B. isosceles