Similar Triangles
Telangana SSC Class 10 • Proportional sides • Equal angles • Area ratio
📘 Concept
Two triangles are called similar (△ABC ~ △DEF) if:
- All corresponding angles are equal: ∠A = ∠D, ∠B = ∠E, ∠C = ∠F
- All corresponding sides are proportional:
AB / DE = BC / EF = AC / DF
If △ABC ~ △DEF and the scale factor is k (for example, DE = k·AB), then:
- DE = k·AB, EF = k·BC, DF = k·AC
- Area(DEF) / Area(ABC) = k²
We use this to find missing sides in similar triangles and to prove results in geometry.