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Congruence, Similarity, Right Triangles & Trig - 46%


Circles, Geometric Measurement & Geometric Properties with Equations - 38%


Modeling with Geometry - 16%


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What You Need To Know...

MAFS.912.G-CO.3.10 - Prove theorems about triangles. 

1. The benchmark will be assessed using Drag and Drop Response, Hot Text Response, Movable Text Response, Multi-select Response, Multiple choice Response, Open Response, or Selectable Text.

2. Theorems are restricted to: measures of interior angles of a triangle sum to 180°; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.

3. Items can include narrative proofs, flow-chart proofs, two-column proofs, or informal proofs.

4. Items may require students to give statements and/or justifications to complete formal and informal proofs.


Example One

Example Two

CO3 10 Ex2
                  Click For Solution 

Example Three

Nancy wrote a proof about the figure shown below.


In the proof below, Nancy started with the fact that XZ is a perpendicular bisector of WY and proved that  Triangle Marking WYZ is isosceles.


Which of the following correctly replaces the question mark in Nancy's proof?

  1. ASA
  2. SAA
  3. SAS
  4. SSS


Click for Solution

Additional Examples

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Use Triangle Congruence
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Triangle Midsegment
Congruence of Medians

Reference Sheet


Select sample problems taken from FLDVIPN teacher materials

Violet Esopakis - Palm Beach Co.
Stephanie Fitzwater - Seminole Co.
Angela Kerins - Orange Co.
Lisa Lasseter - St. Johns Co.
Jodi Van Wagoner - Brevard Co.