- Congruent Triangles:
- Angles: ∠A ≅ ∠D, ∠B ≅ ∠E, ∠C ≅ ∠F
- Sides: AB ≅ DE, BC ≅ EF, CA ≅ FD
- Words: Corresponding angles and sides are equal in measure and length.
- Example 1: △IJK ≅ △ABC
- Example 2: IK = VX, KJ = XW, JI = WV
- Similar Triangles:
- Angles: ∠A ≅ ∠D, ∠B ≅ ∠E, ∠C ≅ ∠F
- Sides: AB = k·DE, BC = k·EF, CA = k·FD (where k is the scale factor)
- Words: Corresponding angles are equal; corresponding sides are proportional by a scale factor.
- Example 1: △KLM ~ △DEF
- Example 2: For △BCD ~ △LMN, the missing side DC can be found using proportion: DC / LN = BC / LM → DC / 28 = 169 / 26 → DC = (169 × 28) / 26 = 182.
Parent Tip: Review the logic above to help your child master the concept of similarity and congruence worksheet.
