isosceles trapezoid
Sign in to saveAlso known as cyclic trapezoid, equidiagonal trapezoid, isosceles trapezium, isosceles trapezoid (inclusive)
trapezoid symmetrical about an axis
Key facts
- Type
- quadrilateral , trapezoid
- Properties
- convex , cyclic
- Dual polygon
- Kite
via Wikipedia infobox
Wikidata facts
- Subclass of
- equidiagonal quadrilateral
Show 4 more facts
- Commons category
- Isosceles trapezoids
- has facet polytope
- edge
- dual to
- kite
- maintained by WikiProject
- WikiProject Mathematics
Sources (1)
via Wikidata · CC0
~9 min read
Encyclopedic overview
In Euclidean geometry, an isosceles trapezoid or isosceles trapezium is a convex quadrilateral with a line of symmetry bisecting one pair of opposite sides. It is a special case of a trapezoid. Alternatively, it can be defined as a trapezoid in which both legs and both base angles are of equal measure, or as a trapezoid whose diagonals have equal length. Note that a non-rectangular parallelogram is not an isosceles trapezoid because of the second condition, or because it has no line of symmetry. In any isosceles trapezoid, two opposite sides (the bases) are parallel, and the two other sides (the legs) are of equal length (properties shared with the parallelogram), and the diagonals have equal length. The base angles of an isosceles trapezoid are equal in measure (there are in fact two pairs of equal base angles, where one base angle is the supplementary angle of a base angle at the other base).
Special cases
Excerpted from Wikipedia’s “isosceles trapezoid” article, available under the CC BY-SA 4.0 licence.