Congruent Triangles std8 Page-24.1.2 EM
📐 Two Triangles | Find Equal Sides
ΔLMN: LN = 3cm, ∠L = 30°, ∠M = 80° | ΔXYZ: XY = 3cm, ∠X = 70°, ∠Y = 30°
△ LMN
∠L = 30°
∠M = 80°
∠N = 70°
△ XYZ
∠X = 70°
∠Y = 30°
∠Z = 80°
🔍 ASA Congruence Criterion: Two angles and the included side are equal
📐 Triangles are congruent → corresponding sides are equal
✍️ Find the equal sides of the two triangles
1 Third angle of ΔLMN
In ΔLMN, ∠L = 30°, ∠M = 80°. Find ∠N.
2 Third angle of ΔXYZ
In ΔXYZ, ∠X = 70°, ∠Y = 30°. Find ∠Z.
3 Identify equal angles
Which angles are equal in both triangles?
4 Included side in ΔLMN
In ΔLMN, the side between ∠L (30°) and ∠M (80°) is LM. But we are given LN. Which side is between ∠L and ∠N?
5 Included side in ΔXYZ
In ΔXYZ, which side is between ∠X (70°) and ∠Z (80°)?
6 Identify the correspondence
Looking at the angles, we see ∠L = 30° = ∠Y, ∠M = 80° = ∠Z, ∠N = 70° = ∠X. What is the correct correspondence?
7 Side equal to LN
In ΔLMN, LN is between ∠L (30°) and ∠N (70°). Which side of ΔXYZ is between ∠Y (30°) and ∠X (70°)?
8 Length of XY
What is the length of XY? (Given)
9 Side equal to LM
LM is between ∠L (30°) and ∠M (80°). Which side of ΔXYZ is between ∠Y (30°) and ∠Z (80°)?
10 Side equal to MN
MN is opposite ∠L (30°). Which side of ΔXYZ is opposite ∠Y (30°)?