🔺 Similar Triangles Calculator
Check if two triangles are similar
Triangle 1
Triangle 2
How to Use This Calculator
Enter Triangle 1 Sides
Input the three side lengths of the first triangle.
Enter Triangle 2 Sides
Input the three side lengths of the second triangle.
Check Similarity
Click "Check Similarity" to determine if the triangles are similar.
Review Results
See if triangles are similar and the scale factor if they are.
Formula
Triangles are similar if side ratios are equal
a₂/a₁ = b₂/b₁ = c₂/c₁ = k (scale factor)
Similarity Condition:
Two triangles are similar if corresponding sides are proportional (have the same ratio).
Scale Factor:
If triangles are similar, the constant ratio k is called the scale factor.
Other Similarity Tests:
- SSS (Side-Side-Side): All three sides proportional
- SAS (Side-Angle-Side): Two sides proportional and included angle equal
- AA (Angle-Angle): Two angles equal
About Similar Triangles Calculator
The Similar Triangles Calculator determines if two triangles are similar by comparing their side ratios. Similar triangles have the same shape but different sizes - all corresponding angles are equal and corresponding sides are proportional.
When to Use This Calculator
- Geometry: Verify triangle similarity in problems
- Education: Learn about similar triangles
- Construction: Scale triangular designs
- Engineering: Analyze similar structures
Why Use Our Calculator?
- ✅ Quick Check: Instantly determine similarity
- ✅ Scale Factor: Calculate the ratio between triangles
- ✅ Accurate: Uses precise mathematical comparison
- ✅ Educational: Helps understand similarity concepts
- ✅ Free: No registration required
Key Properties
- Corresponding Angles: All three angles are equal in similar triangles
- Proportional Sides: Corresponding sides have the same ratio
- Area Ratio: If scale factor is k, area ratio is k²
- Perimeter Ratio: Perimeter ratio equals the scale factor k
Frequently Asked Questions
What makes triangles similar?
Triangles are similar if their corresponding angles are equal and their corresponding sides are proportional (have the same ratio).
What is the scale factor?
The scale factor (k) is the constant ratio of corresponding sides. If Triangle 2 is k times Triangle 1, then k is the scale factor.
Do similar triangles have the same area?
No, similar triangles have proportional areas. If the scale factor is k, the area ratio is k².
Can I check similarity with angles?
Yes! If two angles are equal, the triangles are similar (AA similarity). This calculator uses side ratios (SSS similarity).