Answer:
Yes, the sides form a right triangle.
Step-by-step explanation:
Pythagorean Theorem:
a² + b² = c²
↓
20² + 21² = 29²
║a² = 20² = 400
║b² = 21² = 441
║c² = 29² = 841
↓
400 + 441 = 841
║This equation is true.
↓
Yes, the sides form a right triangle.
