To determine if triangles ΔWXZ and ΔYZX are congruent, we can analyze the information given:
- Both angles WXZ and XZY are right angles. This means both triangles are right triangles.
- The lengths of sides WX and ZY are both 21 centimeters. Therefore, WX = ZY.
- The triangles share the side XZ.
To apply the SAS (Side-Angle-Side) criterion for triangle congruence, we need two sides and the included angle to be congruent in both triangles.
- We have one pair of congruent sides: WX = ZY = 21 cm.
- The included angles that they form with the side XZ (angles WXZ and YZX) are both right angles (90°), which means they are also congruent.
Now we can conclude that we have:
- Side WX = Side ZY
- Angle WXZ = Angle YZX (both right angles)
- Side XZ is common to both triangles.
Thus, by the SAS criterion, we can say that ΔWXZ ≅ ΔYZX.
Therefore, the correct option is: Yes, they are congruent by SAS.