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Similarity Squad

A comprehensive guide to understanding geometric similarity, covering ratios, proportions, and similarity criteria for polygons and triangles.

WMWilkzhie Maria Silva Moncada

Similarity Squad

A comprehensive guide to understanding geometric similarity, covering ratios, proportions, and similarity criteria for polygons and triangles.

WMWilkzhie Maria Silva Moncada

\(\frac{\text{Small Side A}}{\text{Large Side A}} = \frac{\text{Small Side B}}{\text{Large Side B}}\)

Indirect Measurement Case

6ft

4ft shadow

\(x\)

16ft shadow

\(\frac{6}{x} = \frac{4}{16} \implies 4x = 96 \implies x = 24\)

FILE 08

Proportional Relationships

Triangle Proportionality Theorem

If a line is parallel to one side of a triangle and intersects the other two sides, then it divides the two sides proportionally.

If \(DE \parallel BC\), then:

\(\frac{AD}{DB} = \frac{AE}{EC}\)

A D E B C a b c d

Parallel Indicator

GEOMETRY INVESTIGATION UNIT AGENT RECORD #SIM-04-C PAGE 3 OF 3

  • Set up a Proportion using matching ratios.
  • Cross-multiply and solve for the variable.
  • Equation Skeleton

    \(\frac{\text{Small Figure}}{\text{Large Figure}} = \frac{\text{Small Figure}}{\text{Large Figure}}\)

    Indirect Measurement Case

    6ft

    4ft shadow

    \(x\)

    16ft shadow

    \(\frac{6}{x} = \frac{4}{16} \implies 4x = 96 \implies x = 24\)

    FILE 08

    Proportional Relationships

    Triangle Proportionality Theorem

    If a line is parallel to one side of a triangle, it divides the other two sides proportionally.

    If \(DE \parallel BC\), then:

    \(\frac{AD}{DB} = \frac{AE}{EC}\)

    A D E B C a b c d

    Parallel Indicators

    GEOMETRY INVESTIGATION UNIT AGENT RECORD #SIM-04-C PAGE 3 OF 3

    \(\frac{\text{Known}_1}{\text{Target}_x} = \frac{\text{Ratio Part}_1}{\text{Ratio Part}_2}\)

    10

    x

    Shadow Mapping

    REF #SIM-26-P2 SUBJECT: TRIANGLE INVESTIGATION

    Advanced Intel

    Proportional Relations

    Extended Theorems & Relationships

    THEOREMS 08

    Triangle Proportionality

    Theorem: If a line is parallel to one side of a triangle and intersects the other two sides, it divides them proportionally.

    If \(DE \parallel BC\), then: \(\frac{AD}{DB} = \frac{AE}{EC}\)

    Parallel Evidence Required

    THEOREMS 09

    Parallel Line Proportions

    Theorem: If three or more parallel lines intersect two transversals, then they cut the transversals proportionally.

    \(\frac{AB}{BC} = \frac{DE}{EF}\)

    THEOREMS 10

    Similarity & Scaling

    Proportional Perimeters & Areas

    Perimeter Ratio

    Matches the scale factor of sides.

    \(k\)

    Area Ratio

    Matches the square of the scale factor.

    \(k^2\)

    Agent Note: If side ratio is \(2:3\), then perimeter ratio is \(2:3\) and area ratio is \(4:9\).

    REF #SIM-26-P3 SUBJECT: ADVANCED PROPORTIONALITY

    \(\frac{a}{b} = \frac{c}{d}\)

    Chart 09

    Parallel Lines Theorem

    Theorem: 3+ parallel lines cut transversals into proportional segments.

    Chart 10

    Similarity & Scaling

    The Relation of Dimensions

    Perimeter Ratio

    \(k\)

    (Same as sides)

    Area Ratio

    \(k^2\)

    (Sides Squared)

    Field Example:

    If side ratio is 1:3,

    then area ratio is 1:9.

    File Ref: 404-SIM-03 Investigation Phase III: Scaling

    Triangle Proportionality

    The Theorem: If a line parallel to one side of a triangle intersects the other two sides, it divides them proportionally.

    \(\frac{\text{Part A}}{\text{Part B}} = \frac{\text{Part C}}{\text{Part D}}\)

    Parallel Condition Required

    Chart 09

    Parallel Line Proportions

    The Theorem: If three or more parallel lines intersect two transversals, then they divide the transversals proportionally.

    Chart 10

    Similarity & Scaling

    Proportionality of Dimensions

    Perimeter Ratio

    \(k\)

    (Matching Side Ratio)

    Area Ratio

    \(k^2\)

    (Side Ratio Squared)

    Proof Example:

    If side ratio is 2:5,

    then area ratio is 4:25.

    File Ref: 404-SIM-P3 Investigation Phase III: Scaling Laws

    The Theorem: If a line parallel to one side of a triangle intersects the other two sides, it divides them proportionally.

    \(\frac{\text{Part A}}{\text{Part B}} = \frac{\text{Part C}}{\text{Part D}}\)

    Parallel Condition Required

    Chart 09

    Parallel Line Proportions

    The Theorem: If three or more parallel lines intersect two transversals, then they divide the transversals proportionally.

    Chart 10

    Similarity & Scaling

    Proportionality of Dimensions

    Perimeter Ratio

    1

    2

    \(k\)

    Area Ratio

    1

    \(k^2\)

    Proof Example:

    If side ratio is 2:5,

    then area ratio is 4:25.

    File Ref: 404-SIM-P3 Investigation Phase III: Scaling Laws

    Extended Laws of Similarity

    Chart 08

    Triangle Proportionality

    The Theorem: If a line parallel to one side of a triangle intersects the other two sides, it divides them proportionally.

    \(\frac{\text{Part A}}{\text{Part B}} = \frac{\text{Part C}}{\text{Part D}}\)

    Parallel Condition Required

    Chart 09

    Parallel Line Proportions

    The Theorem: If three or more parallel lines intersect two transversals, then they divide the transversals proportionally.

    Chart 10

    Similarity & Scaling

    Proportionality of Dimensions

    Perimeter Ratio

    1

    2

    \(k\)

    Area Ratio

    1

    \(k^2\)

    Proof Example:

    If side ratio is 2:5,

    then area ratio is 4:25.

    File Ref: 404-SIM-P3 Investigation Phase III: Scaling Laws

    Proportionality Theorems

    Extended Laws of Similarity

    Chart 08

    Triangle Proportionality

    The Theorem: If a line parallel to one side of a triangle intersects the other two sides, it divides them proportionally.

    \(\frac{\text{Part A}}{\text{Part B}} = \frac{\text{Part C}}{\text{Part D}}\)

    A B C D

    Parallel Condition Required

    Chart 09

    Parallel Line Proportions

    The Theorem: If three or more parallel lines intersect two transversals, then they divide the transversals proportionally.

    A

    C

    B

    D

    \(\frac{A}{B} = \frac{C}{D}\)

    Chart 10

    Similarity & Scaling

    Proportionality of Dimensions

    Perimeter Ratio

    1

    2

    \(k\)

    Area Ratio

    1

    \(k^2\)

    Proof Example:

    If side ratio is 2:5,

    then area ratio is 4:25.

    File Ref: 404-SIM-P3 Investigation Phase III: Scaling Laws

    Advanced Intel

    Proportionality Theorems

    Extended Geometric Laws

    Chart 08

    Triangle Proportionality

    The Theorem: A line parallel to one side of a triangle intersects the other two sides, it divides them proportionally.

    \(\frac{A}{B} = \frac{C}{D}\)

    A B C D

    Condition: Parallel Line (\(\parallel\))

    Chart 09

    Parallel Line Proportions

    The Theorem: 3+ parallel lines cut transversals into proportional segments.

    W

    Y

    X

    Z

    \(\frac{W}{X} = \frac{Y}{Z}\)

    Chart 10

    Similarity & Scaling

    Proportionality of Dimensions

    Perimeter Ratio

    1

    2

    \(k\)

    (Same as sides)

    Area Ratio

    1

    \(k^2\)

    (Sides squared)

    Field Evidence:

    If side ratio is 2:5,

    then Area ratio is 4:25.

    File Ref: 404-SIM-P3 Investigation: Scaling Laws

    Advanced Intel

    Proportionality Theorems

    Extended Laws of Similarity

    Chart 08

    Triangle Proportionality

    The Theorem: If a line is parallel to one side of a triangle, it divides the other two sides proportionally.

    \(\frac{A}{B} = \frac{C}{D}\)

    A B C D

    Condition: Parallel Line (\(\parallel\))

    Chart 09

    Parallel Line Proportions

    The Theorem: 3+ parallel lines cut transversals into proportional segments.

    W

    Y

    X

    Z

    \(\frac{W}{X} = \frac{Y}{Z}\)

    Chart 10

    Similarity & Scaling

    Proportionality of Dimensions

    Perimeter Ratio

    1

    k

    \(k\)

    Linear Scale

    Area Ratio

    1

    \(k^2\)

    Squared Scale

    Case Study:

    If side ratio is 2:5 (\(k = 2.5\)),

    then Area ratio is 4:25 (\(k^2 = 6.25\)).

    File Ref: 404-SIM-P3 Investigation: Scaling Laws

    Advanced Intel

    Proportionality Theorems

    Extended Laws of Similarity

    Chart 08

    Triangle Proportionality

    The Theorem: If a line is parallel to one side of a triangle, it divides the other two sides proportionally.

    \(\frac{A}{B} = \frac{C}{D}\)

    A B C D

    Condition: Parallel Line (\(\parallel\))

    Chart 09

    Parallel Line Proportions

    The Theorem: 3+ parallel lines cut transversals into proportional segments.

    W

    Y

    X

    Z

    \(\frac{W}{X} = \frac{Y}{Z}\)

    Chart 10

    Similarity Scaling Theorem

    Proportionality of Dimensions

    Perimeter Ratio

    1

    k

    \(k\)

    Linear Scale

    Area Ratio

    1

    \(k^2\)

    Squared Scale

    Case Study:

    If side ratio is 2:5 (\(k = 2.5\)),

    then Area ratio is 4:25 (\(k^2 = 6.25\)).

    File Ref: 404-SIM-P3 Investigation: Scaling Laws

    x

    Shadow B

    \(\frac{6}{x} = \frac{\text{Shadow A}}{\text{Shadow B}}\)

    REF: SIM-DOSSIER-P3 Investigation Phase III: Application

    Intel Update

    Extended Laws

    Chart 08

    Triangle Proportionality

    Theorem: If a line is PARALLEL to one side of a triangle, it divides the other two sides proportionally.

    \(\frac{A}{B} = \frac{C}{D}\)

    A B C D

    Symbol: \(\parallel\)

    Chart 09

    Parallel Line Proportions

    Theorem: If three or more parallel lines intersect two transversals, they divide them proportionally.

    W

    Y

    X

    Z

    \(\frac{W}{X} = \frac{Y}{Z}\)

    Chart 10

    The Scaling Laws

    Perimeter Ratio

    1

    k

    \(k\)

    Linear Proportions

    Area Ratio

    1

    \(k^2\)

    Squared Proportions

    Field Note:
    If the Side Ratio is 2:5,
    then the Area Ratio is 4:25.

    REF: SIM-DOSSIER-P4 Investigation Phase IV: Laws

    \(\frac{A}{B} = \frac{C}{D}\)

    A B C D

    REF: SIM-DOS-03 Investigation Phase III

    Intel HQ

    Extended Laws

    Chart 09

    Parallel Line Proportions

    Theorem: 3+ parallel lines divide transversals proportionally.

    W

    Y

    X

    Z

    \(\frac{W}{X} = \frac{Y}{Z}\)

    Chart 10

    Dimension Scaling Laws

    Perimeter Ratio

    1

    k

    \(k\)

    Area Ratio

    1

    \(k^2\)

    Case Brief:

    Side Ratio 2:5 (\(k = 2.5\)) → Area Ratio 4:25 (\(k^2 = 6.25\))

    REF: SIM-DOS-04 Investigation Concluded

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