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Finding the Fourth Proportional to 415.15, 622.90 and 209.78

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Solution

The fourth proportional to 415.15, 622.90 and 209.78 is: 314.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.15 : 622.90 = 209.78 : x
  2. Step 2: Convert to fraction form
    415.15/622.90 = 209.78/x
  3. Step 3: Cross multiply
    415.15x = 622.90 × 209.78
  4. Step 4: Simplify right side
    415.15x = 130,670.91
  5. Step 5: Solve for x
    x = 130,670.91/415.15
  6. Step 6: Final answer
    x = 314.76

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.