Calculate missing side lengths using the property of similarity (proportionality).
Triangle Proportions
Triangle 1 (Known Sides)
Triangle 2 (Missing Sides)
Solution Results
6.00
Missing Side (b2)
Calculated using the ratio of corresponding sides.
Scale Factor (k)0.400
Reciprocal Ratio2.500
Triangle 1
Triangle 2
About this calculator
What are Similar Triangles?
Two triangles are similar if their corresponding angles are equal and their corresponding sides are proportional. This means one triangle is a scaled version of the other. The ratio of any two corresponding sides is constant for all three pairs of sides.
💡
Pro Tips
Ensure you are matching 'corresponding' sides (e.g., shortest side to shortest side).
If the triangles are similar, all angles are identical (AAA).
Areas of similar triangles scale by the square of the side ratio (k²).
!
Fun Facts
"Thales of Miletus used similar triangles to measure the height of the Egyptian pyramids by comparing their shadows to his own shadow."
"The 'Midsegment Theorem' creates a similar triangle that is exactly 1/4 the area of the original."
"All equilateral triangles are similar to each other."
