Hello!
Answer:

Explanation:
→ We want to solve this equation:

◼ Simplify the left side:


◼ Calculate the square root of both sides:

◼ Simplify both sides:

→ We could have used the quadratic form, but calculating the square root of both sides is faster and give the same result.
Conclusion:
The solution of the equation 12² + 10² = c² is √244.