An isosceles triangle has at least two sides of equal length.
Glossary Term: Definitions
A list of geometrical definitions and postulates.
The locus is a set of all points (commonly, a line, a line segment, a curve or a surface), whose location satisfies or is determined by one or more specified conditions.
A cevian that goes through the midpoint of the opposing side. The three medians divide the triangle into six equal-area parts.
A polygon with nine sides.
A polygon with eight sides.
The orthocenter of a triangle is the intersection of its three altitudes.
A two-dimensional curve of which each point lies at equal distance from a point (focus) and a straight line (directrix).
A quadrilateral with two pairs of parallel sides. It’s area is base times height, but also short side times long side times sine of included angle.
The length of the boundary of a two-dimensional shape.
A two-dimensional shape with right sides, for example a triangle or square.