# Common Core Standards: Math See All Teacher Resources

#### The Standards

# High School: Geometry

### Similarity, Right Triangles, and Trigonometry HSG-SRT.B.5

**5. Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures.**

Tom Hanks as Forrest in *Forrest Gump*, Tom Hanks as Ray Peterson in *The 'Burbs*, and Tom Hanks as Chuck Noland in *Cast Away*. Congruent or similar?

Well, they are technically different characters in very different movies. So they'd probably best be described as similar. But based on Hanks's fixation with urinating on camera, they certainly have congruent characteristics.

To truly test for congruence versus similarity, we'd need to evaluate them based on more specific terms. Like which side of the discussion about choosing an even numbered-urinal they come down on. Or their angle on preventing splashback.

Enough pee jokes? Yes, thanks.

The criteria to determine whether triangles are congruent or similar include proportionality or congruency of side lengths and congruency of angles. Fortunately, students don't have to check all three sides and all three angles every time they want to test for congruency or similarity. That would make the process rather inefficient.

And if we've said it once, we've said it a million times: mathematicians thrive on efficiency.

There are several ways to combine the side length proportionality or congruency and angle congruency to check for triangle congruency or similarity. They're various combinations and permutations of the letters S (for side) and A (for angle) and students should already be familiar with them. In fact, they should have mastered these congruency versus similarity tests for triangles.

The Tom Hanks character congruency versus similarity test, however, still needs some work.

### Aligned Resources

- ACT Math 2.1 Plane Geometry
- ACT Math 2.2 Plane Geometry
- Indirect Proofs
- Properties of Equality and Congruence
- Proving Triangles Congruent
- Proving Triangles Congruent 2
- Conditional Statements
- SSS Postulate
- 3-4-5 Triangle: Find the Remaining Side - Math Shack
- 3-4-5 Triangle: Find the Hypotenuse - Math Shack
- 3-4-5 Triangle: Find the Area - Math Shack
- Equilateral Triangle: Find the Area Given the Altitude - Math Shack
- Rectangle: Find the Diagonal - Math Shack
- 30-60-90 Triangle: Find the Hypotenuse - Math Shack
- 30-60-90 Triangle: Find the Area Given Two Sides - Math Shack
- 30-60-90 Triangle: Find the Area Given an Angle - Math Shack
- 30-60-90 Triangle: Find Another Side Given the Area - Math Shack
- 3-4-5 Triangle: Find the Other Leg - Math Shack
- Triangle Congruence - Math Shack
- Identifying Corresponding Parts in Descriptions of Congruent Triangles - Math Shack
- 30-60-90 Triangle: Find the Remaining Side - Math Shack
- 30-60-90 Triangle: Find Another Side Given an Angle - Math Shack
- 30-60-90 Triangles Find the Radical Side - Math Shack
- Right Triangle Geometric Mean - Math Shack
- 45-45-90 Triangles - Math Shack
- Identifying Similar Triangles - Math Shack
- Identifying Scale Factors - Math Shack
- Identifying Scale Factors from Descriptions of Triangles - Math Shack
- Paragraph Proofs - Math Shack
- Geometric Mean - Math Shack