Geometry Matching terms sheet

mid-segment theorem

"In a triangle, the segment joining the midpoints of any two sides will be parallel to the third side and half its length.". add both sides up and divide by 2

scalene triangle

A scalene triangle is a triangle that has three unequal sides, such as those illustrated above.

same-side interior angles

Image result for same-side interior angles The same-side interior angle theorem states that when two lines that are parallel are intersected by a transversal line, the same-side interior angles that are formed are supplementary, or add up to 180 degrees.

equilateral triangle

In geometry, an equilateral triangle is a triangle in which all three sides are equal.

equilateral

In geometry, an equilateral triangle is a triangle in which all three sides are equal. In the familiar Euclidean geometry, equilateral triangles are also equiangular; that is, all three internal angles are also congruent to each other and are each 60°.

Collinear

Points that lie on the same line

Median

Put all the numbers in numerical order. If there is an odd number of results, the median is the middle number.

alternate interior angles

The pairs of angles on opposite sides of the transversal but inside the two lines are called Alternate Interior Angles.

alternate exterior angles

The pairs of angles on opposite sides of the transversal but outside the two lines are called Alternate Exterior Angles.

Theorem

a general proposition not self-evident but proved by a chain of reasoning; a truth established by means of accepted truths.

Axiom or postulate

are assumed to be true without any proof or demonstration.

parallel lines

are lines in a plane which do not meet; that is, two lines in a plane that do not intersect or touch each other at any point are said to be parallel.

skew lines

are two lines that do not intersect and are not parallel.

vertex

common endpoint

vertical angles

each of the pairs of opposite angles made by two intersecting lines.

supplementary angles

either of two angles whose sum is 180°.

complementary angles

either of two angles whose sum is 90°.

coplanar

in the same plane.

right triangle

is 90 degress

perpendicular lines

is the relationship between two lines which meet at a right angle (90 degrees).

obtuse triangle

larger than 90 degrees

acute triangles

less than 90 degrees

linear pair

of angles is formed when two lines intersect.

transverse

situated or extending across something.

isosceles triangle

that has two sides of equal length

corresponding angles

the angles that occupy the same relative position at each intersection where a straight line crosses two others. If the two lines are parallel, the corresponding angles are equal.

Adjacent angles

they have a common side and a common vertex (corner point) and don't overlap.