Ch. 8 Flashcards
Converse of Corresponding Angles Postulate
If 2 lines r intersected by a transversal, & corresponding angles are congruent, then the lines are parallel.
Converse of Cointerior Angles Theorem
If 2 lines r cut by a transv & cointerior angles r supp, then the lines r parallel
Converse of Alt Interior Angles Theorem
If 2 lines r cut by a transv & alt interior angles r congruent, then the lines r parallel
Perpendicular & Parallel Th
If 2 lines r perp 2 the same transversal, then they r parallel.
Perp & Transversal Th
If a transv is perp to one of two parallel lines, then it is also perp to the other line.
trapezoid
quadrilateral with only 1 pair of parallel sides
Triangle Sum Th
the sum of the measures of the angles of a triangle is 180
Quadrilateral Sum Th
The sum of the measures of the angles of a quadrilateral is 360.
Converse of Quadrilateral Th
If both pairs of opp angles of a quadrilateral r equal, then the quadrilateral is a parallelogram.
Exterior Angle Th
An exterior angle of a triangle is equal in measure to the sum of its 2 remote interior angles.
definition of similar
2 triangles are similar iff their vertices can be matched up so that the corresponding angles are equal & corresponding sides are in proportion.
definition of congruent
2 triangles r congruent iff their vertices can be matched up so that the corresponding parts (angles & sides) of the triangles r equal in measure.
Triangle Similarity Postulate (AA Post.)
If 2 angles of a triangle r equal to 2 angles of another triangle, then the 2 triangles are similar.
How to find any angle of a triangle?
A = 1/2ab sin C
trig
SOH CAH TOA
Overlapping Similar Triangles
If a line is drawn from a point on one side of a triangle parallel to another side, then it forms a triangle similar to the original side.
ASA Theorem
If 2 angles & the included side of 1 triangle are equal to the corresponding angles and side of another triangle, then the triangles are congruent.
AAS Theorem
If 2 angles and a non-included side of 1 triangle r equal to corresponding angles and side of another triangle, then the triangles are equal.
ASS
ASS IZ NOT GOOD
SAS Postulate
If 2 sides & the included angle of 2 triangle r equal to the corresponding sides & angle of another triangle, then the triangles r congruent.
angle bisector
a ray that begins in the vertex of an angle & divides the angle into 2 equal parts
segment bisector
a ray, line, or segment that divides a segment into two equal parts
perpendicular bisector
a line, ray, / segment that bisects the segment & is perpendicular to it
Hypotenuse-Leg Theorem
2 right triangles are equal if the hypotenuse & leg of 1 triangle are equal to the hypotenuse & leg of the other triangle
isosceles triangle
a triangle w/ 2 sides = in measure
equilateral triangle
a triangle in which all the sides are equal in measure
equiangular triangle
a triangle in which all the angles are equal in measure
Isosceles Triangle Theorem
If 2 sides of a triangle r = in measure, then the angles opposite those sides are = in measure
Converse of Isosceles Triangle Th
If 2 angles of a triangle r equal in measure, then the sides opposite those angles r = in measure
Equilateral Triangle Th
If a triangle is equilateral, then it’s also equiangular
Converse of Equil Triangle Th
If a triangle is equiangular, then it’s equilateral.
Perpendicular Bisector Th
If a point is the same distance from both ends of a segment, then it lies on the perp bisector of the segment
Similar Right Triangle Th
If the altitude is drawn to the hypotenuse of a right triangle, then the 2 triangles formed r similar to each other & the original triangle.
geometric mean
If a, b, and x r positive numbers, and a/x = x/b, then x is the geometric mean b/w a and b. The GM is ALWAYS the pos root
Geometric Mean Th
If the altitude is drawn to the hyp of a right triangle, then the msr of the altitude is the geometric mean b/w the measures of the parts of the hypotenuse.
30-60-90
Opp 30 - x Hypotenuse - 2x Opp 60 - x[3
45-45-90
Opp 45’s - x Hypotenuse - x[2
trigonometry
SO-CAH-TOA
sin, cos, and tan of 30
1/2, [3/2, [3/3 or 1/[3
sin, cos, and tan of 60
[3/2, 1/2, [3
sin, cos, and tan of 45
[2/2 or 1/[2, [2/2 or 1/[2, 1
Pythagorean Theorem
In any right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the legs. c2 = a2 + b2
If 2 lines r intersected by a transversal, & corresponding angles are congruent, then the lines are parallel.
Converse of Corresponding Angles Postulate
If 2 lines r cut by a transv & cointerior angles r supp, then the lines r parallel
Converse of Cointerior Angles Theorem
If 2 lines r cut by a transv & alt interior angles r congruent, then the lines r parallel
Converse of Alt Interior Angles Theorem
If 2 lines r perp 2 the same transversal, then they r parallel.
Perpendicular & Parallel Th
If a transv is perp to one of two parallel lines, then it is also perp to the other line.
Perp & Transversal Th
quadrilateral with only 1 pair of parallel sides
trapezoid
the sum of the measures of the angles of a triangle is 180
Triangle Sum Th
The sum of the measures of the angles of a quadrilateral is 360.
Quadrilateral Sum Th
If both pairs of opp angles of a quadrilateral r equal, then the quadrilateral is a parallelogram.
Converse of Quadrilateral Th
An exterior angle of a triangle is equal in measure to the sum of its 2 remote interior angles.
Exterior Angle Th
2 triangles are similar iff their vertices can be matched up so that the corresponding angles are equal & corresponding sides are in proportion.
definition of similar
2 triangles r congruent iff their vertices can be matched up so that the corresponding parts (angles & sides) of the triangles r equal in measure.
definition of congruent
If 2 angles of a triangle r equal to 2 angles of another triangle, then the 2 triangles are similar.
Triangle Similarity Postulate (AA Post.)
If a line is drawn from a point on one side of a triangle parallel to another side, then it forms a triangle similar to the original side.
Overlapping Similar Triangles
If 2 angles & the included side of 1 angle are equal to the corresponding angles and side of another triangle, then the angles are congruent.
ASA Theorem
If 2 angles and a non-included side of 1 triangle r equal to corresponding angles and side of another triangle, then the triangles are equal.
AAS Theorem
ASS IZ NOT GOOD
ASS
If 2 sides & the included angle of 2 triangle r equal to the corresponding sides & angle of another triangle, then the triangles r congruent.
SAS Postulate
a ray that begins in the vertex of an angle & divides the angle into 2 equal parts
angle bisector
a ray, line, or segment that divides a segment into two equal parts
segment bisector
a line, ray, / segment that bisects the segment & is perpendicular to it
perpendicular bisector
2 right triangles are equal if the hypotenuse & leg of 1 triangle are equal to the hypotenuse & leg of the other triangle
Hypotenuse-Leg Theorem
a triangle w/ 2 sides = in measure
isosceles triangle
a triangle in which all the sides are equal in measure
equilateral triangle
a triangle in which all the angles are equal in measure
equiangular triangle
If 2 sides of a triangle r = in measure, then the angles opposite those sides are = in measure
Isosceles Triangle Theorem
If 2 angles of a triangle r equal in measure, then the sides opposite those angles r = in measure
Converse of Isosceles Triangle Th
If a triangle is equilateral, then it’s also equiangular
Equilateral Triangle Th
If a triangle is equiangular, then it’s equilateral.
Converse of Equil Triangle Th
If a point is the same distance from both ends of a segment, then it lies on the perp bisector of the segment
Perpendicular Bisector Th
If the altitude is drawn to the hypotenuse of a right triangle, then the 2 triangles formed r similar to each other & the original triangle.
Similar Right Triangle Th
If a, b, and x r positive numbers, and a/x = x/b, then x is the geometric mean b/w a and b. The GM is ALWAYS the pos root
geometric mean
If the altitude is drawn to the hyp of a right triangle, then the msr of the altitude is the geometric mean b/w the measures of the parts of the hypotenuse.
Geometric Mean Th
Opp 30 - x Hypotenuse - 2x Opp 60 - x[3
30-60-90
Opp 45’s - x Hypotenuse - x[2
45-45-90
SO-CAH-TOA
trigonometry
1/2, [3/2, [3/3 or 1/[3
sin, cos, and tan of 30
[3/2, 1/2, [3
sin, cos, and tan of 60
[2/2 or 1/[2, [2/2 or 1/[2, 1
sin, cos, and tan of 45
In any right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the legs. c2 = a2 + b2
Pythagorean Theorem