Geometry Terms - chapter 4 Flashcards
acute triangle
a triangle with three acute angles
auxiliary line
a line drawn in a figure to aid in a proof
base of an isosceles triangle
the side opposite the vertex angle
base angle of an isosceles triangle
one of the two angles that have the base of the triangle as a side
congruent polygons
polygons whose corresponding sides and angles are congruent
coordinate proof
a style of proof that uses coordinate geometry and algebra
corollary
a theorem whose proof follows directly from another theorem
corresponding angles of polygons
angles in the same position in two different polygons that have the same number of angles
corresponding sides of polygons
sides in the same position in two different polygons that have the same number of sides
CPCTC
abbreviation for “Corresponding Parts of Congruent Triangles are Congruent”
dilation
a transformation in which the lines connecting every point P with its image P’ all intersect at a point C, known as the center of dilation, and CP’/CP is the same for every point P
equiangular triangle
a triangle with three congruent angles
equilateral triangle
a triangle with three congruent sides
exterior of a figure
the set of all points outside the figure
exterior angle of a polygon
an angle formed by one side of a polygon and the extension of an adjacent side
included angle
the angle formed by two adjacent sides of a polygon
included side
the common side of two consecutive angles of a polygon
interior of a figure
the set of all points inside the figure
interior angle
an angle formed by two sides of a polygon that have a common vertex
isosceles triangle
a triangle with at least two congruent sides
isometry
a transformation that does not change the size or shape of a figure
legs of an isosceles triangle
the two congruent sides of the isosceles triangle
obtuse triangle
a triangle with one obtuse angle
remote interior angle
an interior angle of a polygon that is not adjacent to the exterior angle
right triangle
a triangle with one right angle
rigid transformation
a transformation that does not change the size or shape of a figure
scalene triangle
a triangle with no congruent sides
triangle rigidity
a property of triangles that states that if the side lengths of a triangle are fixed, the triangle can have only one shape
vertex angle of an isosceles triangle
the angle formed by the legs of an isosceles triangle
