Answer:
(altitude of a triangle)A segment from a vertex perpendicular to the opposite side
(base angles)The two angles that include the base of an isosceles triangle
(base of an isosceles triangle)The third, unequal side of an isosceles triangle
(centroid)A point on the interior of a triangle in which the three medians of the triangle
(median of a triangle)A segment from a vertex to the midpoint of the opposite side intersect
(orthocenter)A point in which the three altitudes of the triangle intersect. It is possible for the orthocenter to occur on the triangle, on the interior of the triangle or on the exterior of the triangle
(vertex angle)The angle formed by the two equal sides of an isosceles trian