We are told that triangle QRS is congruent to triangle WXY. That means all corresponding sides and angles are equal.
Let’s match the vertices based on the order:
△QRS ≅ △WXY
So:
Q ↔ W
R ↔ X
S ↔ Y
That means:
∠Q = ∠W
∠R = ∠X
S = ∠Y
From the diagram:
In △QRS:
- ∠Q = 63°
- ∠S = 37°
- Side QR = 50 mm
In △WXY:
- ∠X = 80° → which corresponds to ∠R (since R ↔ X)
- Side XY = 75 mm → but we don’t need this for angle calculation
- Side YW = 83 mm → also not needed for angle
Wait — let’s double-check the correspondence.
If △QRS ≅ △WXY, then:
Vertex Q corresponds to vertex W
Vertex R corresponds to vertex X
Vertex S corresponds to vertex Y
Therefore:
Angle at Q (∠Q) corresponds to angle at W (∠W)
Angle at R (∠R) corresponds to angle at X (∠X)
Angle at S (∠S) corresponds to angle at Y (∠Y)
We are given in △QRS:
∠Q = 63°
∠S = 37°
So we can find ∠R using triangle angle sum:
Sum of angles in a triangle = 180°
So ∠R = 180° - ∠Q - ∠S = 180° - 63° - 37° = 80°
Now, since ∠R corresponds to ∠X, and we’re told ∠X = 80°, that matches! Good.
Now, we want m∠W. Since ∠W corresponds to ∠Q, and ∠Q = 63°, then ∠W must also be 63°.
Alternatively, we could compute from △WXY directly if we knew two angles, but we only know one angle (∠X = 80°). But because of congruence, we don’t need to — we just map the known angles.
So:
m∠W = m∠Q = 63°
Final Answer:
63
Parent Tip: Review the logic above to help your child master the concept of parts of congruent triangles worksheet.