Perpendicular Bisector

This cross is an example of a perpendicular bisector because the longer part intersects the shorter part at the midpoint, and it forms a 90 degree angle.

Median, Altitude

The black line cutting through the base of this flag is an example of a median of a triangle, which is a segment from a vertex to the midpoint of the opposite side. It is also an example of altitude, which is the perpendicular segment from a vertex to opposite side.

Congruent

These two orange slices are congruent. They are the same size and shape.

Simile: The first orangle half is as big as the second orange half.

Legs & Base of Triangle, Hypotenuse

This image contains four right triangles, one on each side of the square with the green dot in the center.

A right triangle is a triangle with a right angle.

Also within the right triangle are two legs and a hypotenuse. The hypotenuse is the side across from the right angle, and the legs are the sides connecting the right angle.

This right triangle is also an isosceles triangle. The hypotenuse is also the base.

Obtuse Triangle

The ruler that cuts through the frame of the door on my lovely art project is an example of an obtuse triangle.

An obtuse triangle is a triangle with one angle that is greater than 90 degrees, and two that are less than 90 degrees.

Isosceles Triangle, Equilateral Triangle, Acute Triangle

This yield sign is an example of an isosceles triangle, an equilateral triangle, and an acute triangle.

An isosceles triangle is a triangle with at least two sides that are equal in length. This triangle has three.

An equilateral triangle is a triangle with sides that are all equal in length, and it also has equal angle measures.

An acute triangle is a triangle with three angles measuring under 90 degrees.

Triangle's Vertex and Sides, Scalene Triangle, Right Triangle

This fancy ruler is an example of a scalene triangle, as well as a right triangle.

A scalene triangle is a triangle with three sides, each of different length.

A right triangle is a triangle with exactly one right angle, as seen in the top angle on this triangle.

This fancy ruler also can be used to point out a vertex of the triangle, which is any of the three red markings, and the sides of the triangle, which are marked by the yellow lines.

The vertex in a triangle is a point in a triangle.

The sides of a triangle are the lines which make up the triangle.