Conditional Properties

In each statement, if the test expression is true, then the conclusion expression is also assumed to be true. Conditional properties are used to prove theorems.

Right Angle Property (Converse)
if m∠ABC = 90, then ∠ABC is a right angle

Isosceles Triangle
if (△XYZ is a triangle) and (segment XY ≅ segment YZ), then △XYZ is an isosceles triangle

Angle Bisector Property
if ray BD bisects ∠ABC, then m∠ABD = m∠DBC

Angle Bisector Property (Converse)
if m∠ABD = m∠DBC, then ray BD bisects ∠ABC

Bisector Angle
if ray BD bisects ∠ABC, then m∠DBC = (m∠ABC) / 2

Angle Bisector Property 2
if (ray BD bisects ∠ABC) and (m∠BPD = 180) and (PMMB) and (PNNB), then distance PM = distance PN

Angle Bisector Property 3
if (distance PM = distance PN) and (PMMB) and (PNNB), then ray BP bisects ∠ABC

Acute Triangle
if (∠ABC is an acute angle) and (∠BCA is an acute angle) and (∠CAB is an acute angle), then △ABC is an acute triangle

Definition of Acute Angle
if ∠ABC is an acute angle, then m∠ABC < 90

Length is Sum of Parts
if m∠ABC = 180, then (distance AB) + (distance BC) = distance AC

Collinear Points Property
if m∠ABC = 180, then m∠BCX = m∠ACX

Collinear Points Property 2
if m∠ABC = 180, then m∠ABC = (m∠ABX) + (m∠XBC)

Midpoint Property
if M is the midpoint of line AB, then distance AM = distance MB

Midpoint Property (Converse)
if (distance AM = distance MB) and (m∠AMB = 180), then M is the midpoint of line AB

Angle Formed by Midpoint
if M is the midpoint of line AB, then m∠AMB = 180

Midpoint is Halfway
if M is the midpoint of line AB, then the x coordinate of point M = ((the x coordinate of point A) + (the x coordinate of point B)) / 2

Midpoint is Halfway 2
if M is the midpoint of line AB, then the y coordinate of point M = ((the y coordinate of point A) + (the y coordinate of point B)) / 2

Complementary Angles
if ∠ABC and ∠DEF are complementary, then (m∠ABC) + (m∠DEF) = 90

Supplementary Angles Property
if ∠ABC and ∠DEF are supplementary, then (m∠ABC) + (m∠DEF) = 180

Supplementary Angles Property (Converse)
if (m∠ABC) + (m∠DEF) = 180, then ∠ABC and ∠DEF are supplementary

Corresponding Angles
if m∠CDE = m∠CAB, then DE || AB

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if (AB || CD) and (∠ABD is a right angle), then ∠BDC is a right angle

Parallel Lines Property 2
if AB || CD, then BA || DC

Parallel Lines Property 3
if AB || CD, then CD || AB

Parallel Lines Property 4
if (AB || YZ) and (m∠ABC = 180), then BC || YZ

Parallel Lines Property 5
if (AB || YZ) and (m∠AXB = 180), then AX || YZ

Extended Parallel Lines
if (AB || YZ) and (m∠ABC = 180) and (m∠XYZ = 180), then AC || XZ

Extended Parallel Lines 2
if (AB || XY) and (m∠ABC = 180) and (m∠XYZ = 180), then AC || XZ

Extended Parallel Lines 3
if (AC || XZ) and (m∠ABC = 180) and (m∠XYZ = 180), then AB || YZ

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if (AC || XZ) and (m∠ABC = 180) and (m∠XYZ = 180), then AB || XY

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if (AB || CD) and (m∠AXB = 180) and (m∠CYD = 180), then XB || CY

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if (AB || CD) and (m∠AXY = 180) and (m∠XYB = 180), then XY || CD

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if ABCD is a square, then ABCD is a rectangle

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if ABCD is a square, then distance AB = distance BC

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if (ABCD is a rectangle) and (distance AB = distance BC), then ABCD is a square

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if m∠abc = 90, then area of △ABC = (((distance AB) ⋅ (distance BC)) ⋅ 1) / 2

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if AB || CD, then not(line AB intersects line CD)

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if AB || CD, then (m∠BAC) + (m∠ACD) = 180

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if (m∠BAC) + (m∠ACD) = 180, then AB || CD

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if (m∠DBA) + (m∠CDB) = 180, then AB || CD

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if △ABC ≅ △DEF, then area of △ABC = area of △DEF

Congruent Triangles Property
if △ABC ≅ △DEF, then △BCA ≅ △EFD

Congruent Triangles Property 2
if △ABC ≅ △DEF, then △BAC ≅ △EDF

Congruent Triangles Property 3
if △ABC ≅ △DEF, then △DEF ≅ △ABC

Transitive Property of Congruent Triangles
if (△ABC ≅ △DEF) and (△DEF ≅ △GHI), then △ABC ≅ △GHI

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if (distance AB = distance DE) and (m∠ABC = m∠DEF) and (distance BC = distance EF), then area of △ABC = area of △DEF

SAS Property
if (distance AB = distance DE) and (m∠ABC = m∠DEF) and (distance BC = distance EF), then △ABC ≅ △DEF

ASA Property
if (m∠ABC = m∠DEF) and (distance BC = distance EF) and (m∠BCA = m∠EFD), then △ABC ≅ △DEF

SSS Property
if (distance AB = distance DE) and (distance BC = distance EF) and (distance CA = distance FD), then △ABC ≅ △DEF

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if (m∠ABC = m∠DEF) and (distance BC = distance EF) and (m∠BCA = m∠EFD), then area of △ABC = area of △DEF

Congruent Triangles Property 4
if △ABC ≅ △DEF, then m∠ABC = m∠DEF

Congruent Triangles Property 5
if △ABC ≅ △DEF, then m∠CAB = m∠FDE

Congruent Triangles Property 6
if △ABC ≅ △DEF, then m∠BCA = m∠EFD

Congruent Triangles Property 7
if △ABC ≅ △DEF, then distance AB = distance DE

Congruent Triangles Property 8
if △ABC ≅ △DEF, then distance BC = distance EF

Congruent Triangles Property 9
if △ABC ≅ △DEF, then distance CA = distance FD

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if (distance AB = distance BC) and (distance BC = distance CD) and (distance CD = distance DA) and (m∠ABC = 90), then ABCD is a square

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if ABCD is a square, then area of quadrilateral ABCD = (distance AB) ⋅ (distance AB)

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if m∠ABC = 180, then area of △ACD = area of quadrilateral ABCD

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if m∠ABC = 180, then area of quadrilateral XABC = area of △XAC

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if m∠ABC = 180, then area of pentagon ACDEF = area of hexagon ABCDEF

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if m∠DEF = 180, then area of hexagon ABCDEF = area of pentagon ABCDF

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if (m∠ABC = 90) and (m∠DEF = 180), then m∠ABC < m∠DEF

Intersecting Lines Property
if line AB intersects line CD at point X, then m∠AXB = 180

Intersecting Lines Property 2
if line AB intersects line CD at point X, then m∠CXD = 180

Collinear Points Property 3
if (m∠ABD = 180) and (m∠ACD = 180), then m∠ABC = 180

Collinear Points Property 4
if (m∠ABD = 180) and (m∠ACD = 180), then m∠BCD = 180

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if (m∠ABC = 180) and (m∠BCD = 180), then m∠ABD = 180

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if (m∠ABC = 180) and (m∠BCD = 180), then m∠ACD = 180

Parallel Lines Property
if (AB || CD) and (line AB intersects line EF at point X), then line EF intersects line CD at point Z

Parallelogram Property
if (AB || CD) and (AC || BD), then ABDC is a parallelogram

Parallelogram Property 2
if ABCD is a parallelogram, then AB || DC

Parallelogram Property 3
if ABCD is a parallelogram, then AD || BC

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if ABCD is a rectangle, then ABCD is a parallelogram

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if ABCD is a rectangle, then ∠ABC is a right angle

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if (ABCD is a parallelogram) and (∠ABC is a right angle), then ABCD is a rectangle

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if (ABCD is a parallelogram) and (∠CDA is a right angle), then ABCD is a rectangle

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if ABCD is a rhombus, then ABCD is a parallelogram

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if ABCD is a rhombus, then distance AB = distance BC

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if (ABCD is a parallelogram) and (distance AB = distance BC), then ABCD is a rhombus

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if (ABCD is a parallelogram) and (distance CD = distance DA), then ABCD is a rhombus

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if (ABCD is a parallelogram) and (distance DA = distance AB), then ABCD is a rhombus

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if (m∠ABC = m∠BCA) and (m∠BCA = m∠CAB), then △ABC is an equilateral triangle

Equilateral Triangle Property
if △ABC is an equilateral triangle, then distance AB = distance BC

Equilateral Triangle Property 2
if △ABC is an equilateral triangle, then distance AB = distance AC

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if (distance AB = distance BC) and (distance BC = distance CA), then △ABC is an equilateral triangle

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if quadrilateral ABCD is an isosceles trapezoid, then AB || DC

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if quadrilateral ABCD is an isosceles trapezoid, then distance AD = distance BC

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if quadrilateral ABCD is a trapezoid, then AB || DC

Slope Property
if slope of line AB = slope of line CD, then AB || CD

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if slope of line AB = 0, then distance AB = (the x coordinate of point B) - (the x coordinate of point A)

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if (m∠ABC = m∠DEF) and (m∠BCA = m∠EFD) and (m∠CAB = m∠FDE) and ((distance AB) / (distance DE) = (distance BC) / (distance EF)) and ((distance BC) / (distance EF) = (distance CA) / (distance FD)), then △ABC ∼ △DEF

Similar Angles Property
if △ABC ∼ △DEF, then m∠ABC = m∠DEF

Similar Angles Property 2
if △ABC ∼ △DEF, then m∠BCA = m∠EFD

Similar Angles Property 3
if △ABC ∼ △DEF, then m∠CAB = m∠FDE

Proportions in Similar Triangles
if △ABC ∼ △DEF, then (distance CB) / (distance FE) = (distance CA) / (distance FD)

Proportions in Similar Triangles 2
if △ABC ∼ △DEF, then (distance CA) / (distance FD) = (distance BC) / (distance EF)

Proportions in Similar Triangles 3
if △ABC ∼ △DEF, then (distance AC) / (distance DF) = (distance AB) / (distance DE)

Proportions in Similar Triangles 4
if △ABC ∼ △DEF, then (distance CA) / (distance FD) = (distance AB) / (distance DE)

Proportions in Similar Triangles 5
if △ABC ∼ △DEF, then (distance AB) / (distance DE) = (distance BC) / (distance EF)

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