Please read our Privacy Policy . A triangle can be in more than one plane at a time. A heptagon has 7 sides and 6 angles. The angles in a regular polygon are congruent. The sum of the measures of the angles in a triangle is 180 degrees.
All polygons have four sides.
All quadrilaterals have four angles. A pentagon can be separated into 3 triangles. A triangle has only 2 vertices.