internal angle
Corner within shape
An internal angle is the angle formed inside a polygon where two adjacent sides meet.
A triangle has three internal angles that always sum to 180 degrees; a quadrilateral's sum to 360.
The term distinguishes from external angles, which are measured outside the shape: The internal angles of a regular hexagon are each 120 degrees.
Units of measurement
- protractorAngle-measuring instrument
- acuteIntensely severe or perceptive
- obtuseLacking mental sharpness
- rightMorally proper or entitled
reflex · straight · bisector · complementary · supplementary · adjacent · radians · arc
Point where edges converge
- polygonMultisided plane figure
- triangleThree-sided plane figure
- quadrilateralFour-sided closed figure
- pentagonFive-sided closed figure
hexagon · octagon · exterior · convex · concave · regular · irregular · diagonal
Occur in succession
- correspondingMatching in character
- transversalLine crossing multiple others
- parallelEquidistant at all points
- perpendicularAt right angles
congruent · equal · opposite · vertical · allied · consecutive
degrees
Units of measurement
- protractorAngle-measuring instrument
- acuteIntensely severe or perceptive
- obtuseLacking mental sharpness
right · reflex · straight · bisector · complementary · supplementary · adjacent · radians · arc · magnitude
vertex
Point where edges converge
- polygonMultisided plane figure
- triangleThree-sided plane figure
- quadrilateralFour-sided closed figure
pentagon · hexagon · octagon · exterior · convex · concave · regular · irregular · diagonal · side
alternate
Occur in succession
- correspondingMatching in character
- transversalLine crossing multiple others
- parallelEquidistant at all points
perpendicular · congruent · equal · opposite · vertical · allied · consecutive