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Finding the Fourth Proportional to 420.27, 629.79 and 391.52

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Solution

The fourth proportional to 420.27, 629.79 and 391.52 is: 586.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.27 : 629.79 = 391.52 : x
  2. Step 2: Convert to fraction form
    420.27/629.79 = 391.52/x
  3. Step 3: Cross multiply
    420.27x = 629.79 × 391.52
  4. Step 4: Simplify right side
    420.27x = 246,572.23
  5. Step 5: Solve for x
    x = 246,572.23/420.27
  6. Step 6: Final answer
    x = 586.70

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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.