Question

Please help me out..(:

Answer 1

Let's call the left side of this tirangle y and downside z.

3² + 6² = y²

y² = 45

y² + z² = (3 + x)²

45 + z² = 9 + 6x + x²

x² + 6² = z²

45 + x² + 6² = 9 + 6x + x²

45 + x² + 36 = 9 + 6x + x²

45 + 36 - 9 = 6x

72 = 6x

x = 12