If the hypotenuse and a leg of one right triangle are congruent to the hypotenuse and a leg of another right triangle, then the triangles are congruent.
Back
Triangle Midsegment Theorem
Front
If a segment joins the midpoints of two sides of a triangle, then the segment is parallel to the third side and is half as long.
Back
obtuse triangle
Front
a triangle with one obtuse angle
Back
Third Angles Theorem
Front
If two angles of one triangle are congruent to two angles of another triangle, then the third angles are also congruent.
Back
Midpoint
Front
A point that divides a segment into two congruent segments
Back
Linear Pair Postulate
Front
If two angles form a linear pair, then they are supplementary
Back
Angle-Angle-Side (AAS)
Front
If two angles and a non-included side of one triangle are congruent to two angles and the corresponding non-included side of a second triangle, then the two triangles are congruent.
Back
Corresponding Angles Postulate
Front
If two parallel lines are cut by a transversal, then the pairs of corresponding angles are congruent
Back
Side-Side-Side (SSS)
Front
If three sides of one triangle are congruent to three sides of another triangle, then the triangles are congruent.
Back
complementary angles
Front
Two angles whose sum is 90 degrees
Back
Transitive
Front
If a=b and b=c, then a=c
Back
Transversal
Front
a line that intersects two or more parallel lines
Back
Same-Side Interior Angles Theorem
Front
If a transversal intersects two parallel lines, then same-side interior angles are supplementary.
Back
Plane
Front
a flat surface that extends forever
Back
equilateral triangle
Front
A triangle with three congruent sides and angles
Back
altitude of a triangle
Front
The altitude of a triangle is a line segment from a vertex that is perpendicular to the opposite side
Back
right triangle
Front
a triangle with one right angle
Back
acute triangle
Front
a triangle with 3 acute angles (less than 90 degrees)
Back
median of a triangle
Front
a segment from a vertex to the midpoint of the opposite side
Back
Perpendicular Bisector Theorem
Front
If a point is on the perpendicular bisector of a segment, then it is equidistant from the endpoints of the segment.
Back
congruent shapes
Front
two figures that have the same size and shape
Back
adjacent angles
Front
Angles that have a common side and a common vertex (corner point).
Back
Orthocenter
Front
The point of concurrency of the altitudes of a triangle
Back
Exterior Angle Theorem
Front
The measure of an exterior angle of a triangle is equal to the sum of the measures of the two nonadjacent interior angles.
Back
segment bisector
Front
a segment, ray, line, or plane that intersects a segment at its midpoint
Back
CPCTC (Corresponding Parts of Congruent Triangles are Congruent)
Front
The definition of congruent triangles; if two triangles are congruent, then the corresponding parts of the congruent triangles are congruent
Back
linear pair
Front
A pair of adjacent angles whose noncommon sides are opposite rays.
Back
Collinear points
Front
Points on the same line
Back
Alternate Interior Angles Theorem
Front
If two parallel lines are cut by a transversal, then the pairs of alternate interior angles are congruent.
Back
Angle Addition Postulate
Front
If P is in the interior of <RST, then m<RSP + m<PST = m<RST
Back
corresponding angles
Front
Angles in the same place on different lines
Back
Ruler Postulate
Front
The points on a line can be matched one to one with the real numbers and you can use it to find the distance between two points
Back
Angle Bisector Theorem
Front
If a point is on the bisector of an angle, then it is equidistant from the two sides of the angle
Back
Side-Angle-Side (SAS)
Front
If two sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then the triangles are congruent.
Back
isosceles triangle
Front
A triangle that has 2 equal sides and 2 equal angles
Back
Distance Formula
Front
d = √[( x₂ - x₁)² + (y₂ - y₁)²]
Back
Alternate Exterior Angles
Front
Angles that lie outside a pair of lines and on opposite sides of a transversal.
Back
Reflexive Property
Front
A quantity is congruent (equal) to itself. a = a
Back
angle bisector
Front
a ray that divides an angle into 2 congruent angles
Back
Alternate exterior angles theorom
Front
If two parallel lines are cut by a transversal, then the alternate interior angles are congruent
Back
Converse of the Perpendicular Bisector Theorem
Front
If a point is equidistant from the endpoints of a segment, then it is on the perpendicular bisector of the segment.
Back
alternate interior angles
Front
Congruent angles between the same pair of parallel lines and on opposite sides of a transversal
Back
supplementary angles
Front
Two angles whose sum is 180 degrees
Back
scalene triangle
Front
a triangle with no congruent sides or angles
Back
Angle-Side-Angle (ASA)
Front
If two angles and the included side of one triangle are congruent to two angles and the included side of another triangle, then the triangles are congruent.
Back
Converse of the Angle Bisector Theorem
Front
If a point in the interior of an angle is equidistant from the sides of the angle, then it is on the bisector of the angle
Back
Coplanar points
Front
points that lie on the same plane
Back
Substitution
Front
<1 + <4 = 180 <4 is congruent to <7
<1 + <7 = 180
Back
Segment Addition Postulate
Front
If B is between A and C, then AB + BC = AC
Back
Section 2
(44 cards)
Trapezoid
Front
A quadrilateral with exactly one pair of parallel sides
Back
Polygon Exterior Angle Sum Theorem
Front
The sum of the measures of the exterior angles of a polygon, one at each vertex, is 360.
Back
If a quadrilateral is a parallelogram, then...
Front
its opposite angles are congruent.
Back
If the diagonals of a parallelogram are congruent
Front
then the parallelogram is a rectangle
Back
If a quadrilateral is a parallelogram, then its diagonals...
Front
bisect each other
Back
Hinge Theorem
Front
If two sides of one triangle are congruent to two sides of another triangle, and the included angle of the first is larger than the included angle of the second, then the third side of the first is longer than the third side of the second.
Back
if both pairs of opposite sides of a quadrilateral are congruent, then...
Front
the quadrilateral is a parallelogram
Back
SOHCAHTOA
Front
SIN (Opposite/Hypotenuse) COS (Adjacent/Hypotenuse) TAN (Opposite/Adjacent)
Back
If a parallelogram is a rectangle then...
Front
its diagonals are congruent
Back
If the diagonals of a parallelogram are perpendicular
Front
then the parallelogram is a rhombus
Back
inscribe
Front
To draw a figure within another so that their boundaries touch but do not intersect.
Back
Radical
Front
the square root of 12 equals 3 radical 2
Back
if a quadrilateral is an isosceles trapezoid, then each pair of...
Front
base angles is congruent
Back
Polygon Angle Sum Theorem
Front
The sum of the measures of the interior angles of an n-gon is (n-2)180
Back
Triangle Inequality Theorem
Front
The sum of the lengths of any two sides of a triangle is greater than the length of the third side.
Back
Pythagorean Theorem
Front
a²+b²=c²
Back
isosceles trapezoid
Front
a trapezoid with congruent legs
Back
Kite Theorem
Front
If a quadrilateral is a kite, then its diagonals are perpendicular.
Back
circumscribe
Front
To draw a figure around another, touching it at points, but not cutting it
Back
the quadrilateral is a parallelogram if the diagonals...
Front
bisect each other
Back
The quadrilateral is a parallelogram if an angle of a quadrilateral is supplementary to both of its...
Front
consecutive angles
Back
equilateral
Front
having all sides equal
Back
Law of Sines
Front
a/sinA = b/sinB = c/sinC
Back
Collary to the Triangle Exterior Angle Theorem
Front
the measure of an exterior angle of a triangle is greater than the measure of each of its remote interior angles
Back
If three (or more) parallel lines cut off congruent segments on one transversal then...
Front
they cut off congruent segments on every transversal
Back
If a parallelogram is a rhombus, then....
Front
its diagonals are perpendicular
Back
If a quadrilateral is a parallelogram, then its opposite sides...
Front
are congruent.
Back
Kite
Front
a quadrilateral with two pairs of consecutive sides congruent and no opposite sides congruent
Back
Trapezoid Midsegment Theorem
Front
If a quadrilateral is a trapezoid, then (1) the midsegment is parallel to the bases, and (2) the length of the midsegment is half the sum of the lengths of the bases
Back
The parallelogram is a rhombus if one diagonal of a parallelogram...
Front
bisects a pair of opposite angles
Back
The quadrilateral is a parallelogram if both pairs of...
Front
opposite sides of a quadrilateral are congruent
Back
Equalangular
Front
all angles are equal
Back
if a quadrilateral is an isosceles trapezoid, then...
Front
the diagonals are congruent in the trapezoid
Back
angle of elevation/depression
Front
the angle formed by a horizontal line and the line of sight to an object above (below) the horizontal line.
Back
If a parallelogram is a rhombus then each...
Front
diagonal bisects a pair of opposite angles
Back
If a quadrilateral is a parallelogram, then its consecutive angles...
Front
are supplementary.
Back
incenter of a triangle
Front
the point of concurrency of the angle bisectors of a triangle
Back
collary to the Polygon Angle Sum Theorem
Front
The measure of each interior angle of a regular n-gon is (n-2)180/n
Back
Centroid
Front
The point of concurrency of the medians of a triangle
Back
circumcenter of a triangle
Front
the point of concurrency of the perpendicular bisectors of a triangle
Back
regular polygon
Front
a polygon that is both equilateral and equilangular
Back
The quadrilateral is a parallelogram if one pair of opposites sides...