internal angles
Angles inside shapes
Internal angles are the angles formed inside a polygon where two sides meet.
A triangle's internal angles always sum to 180 degrees; a quadrilateral's to 360 degrees.
The term distinguishes these from external angles, which are measured outside the shape: The internal angles of a regular hexagon are each 120 degrees.
Point where edges converge
- polygonMultisided plane figure
- quadrilateralFour-sided closed figure
- pentagonFive-sided closed figure
- hexagonSix-sided closed figure
heptagon · octagon · sum · theorem · acute · obtuse · complementary · supplementary
Quadrilateral with paired parallels
- rhombusEquilateral parallelogram
- trapezoidPolygon with parallel pair
- kiteWind-flown tethered toy
- rectangleFour-sided, all right angles
square · decagon · nonagon · dodecagon · tetrahedron · polyhedron · prism · pyramid
Angle-measuring instrument
- degreeUnit of measurement
- radianArc-length angle unit
- calculationMathematical problem-solving process
- bisectorLine splitting something equally
trigonometry · precision · formula · proof · transversal · parallel lines · congruent · arc
vertex
Point where edges converge
- polygonMultisided plane figure
- quadrilateralFour-sided closed figure
- pentagonFive-sided closed figure
hexagon · heptagon · octagon · sum · theorem · acute · obtuse · complementary · supplementary · adjacent
parallelogram
Quadrilateral with paired parallels
rectangle · square · decagon · nonagon · dodecagon · tetrahedron · polyhedron · prism · pyramid · tessellation
protractor
Angle-measuring instrument
- degreeUnit of measurement
- radianArc-length angle unit
- calculationMathematical problem-solving process
bisector · trigonometry · precision · formula · proof · transversal · parallel lines · congruent · arc · subdivision