interior angle
Polygon's inner measurement
An interior angle is an angle formed inside a polygon where two adjacent sides meet.
A triangle has three interior angles that always sum to 180 degrees; a quadrilateral's interior angles sum to 360 degrees.
The term distinguishes these from exterior angles, which are formed outside the polygon by extending one side.
Point where edges converge
- degreesUnits of measurement
- polygonMultisided plane figure
- triangleThree-sided plane figure
- quadrilateralFour-sided closed figure
supplementary · complementary · adjacent · congruent · parallel lines · transversal · alternate · corresponding
Three-sided plane figure
- quadrilateralFour-sided closed figure
- pentagonFive-sided closed figure
- hexagonSix-sided closed figure
- heptagonSeven-sided closed figure
octagon · nonagon · decagon · equilateral · equiangular · regular · irregular · convex polygon
Angle-measuring instrument
- degreeUnit of measurement
- radianArc-length angle unit
- arcminute1/60th of a degree
- arcsecondMinute angular unit
measure · calculate · precision · unit circle · subdivision · calibration · reading · scale
Of great breadth
- bluntDull or tactlessly direct
- obtuse triangleTriangle with angle over ninety
- reflexInvoluntary stimulus response
- openNot closed
Fine-edged, or astute
- narrowOf small width
- acute trianglePolygon with three sub-90° corners
- pointedTapering to a tip
- convergentTending toward union
- perpendicularAt right angles
- orthogonalAt right angles
- right triangleThree-sided, one perpendicular corner
- rectangleFour-sided, all right angles
vertex
Point where edges converge
quadrilateral · supplementary · complementary · adjacent · congruent · parallel lines · transversal · alternate · corresponding · bisector
triangle
Three-sided plane figure
- quadrilateralFour-sided closed figure
- pentagonFive-sided closed figure
- hexagonSix-sided closed figure
heptagon · octagon · nonagon · decagon · equilateral · equiangular · regular · irregular · convex polygon
protractor
Angle-measuring instrument
arcsecond · measure · calculate · precision · unit circle · subdivision · calibration · reading · scale
wide
Of great breadth
- bluntDull or tactlessly direct
- obtuse triangleTriangle with angle over ninety
- reflexInvoluntary stimulus response
sharp
Fine-edged, or astute
- narrowOf small width
- acute trianglePolygon with three sub-90° corners
- pointedTapering to a tip
ninety degrees
- perpendicularAt right angles
- orthogonalAt right angles
- right triangleThree-sided, one perpendicular corner
- geometry termscircle, line, rectangle, side, square
- Trianglestriangle, equilateral, isosceles, scalene, right triangle
- geometry formulasPythagorean theorem, area, perimeter, circumference, surface area
angle, interior, angled, angles, angular, interior angles, interiors