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Finding the Fourth Proportional to 640.61, 884.09 and 391.88

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Solution

The fourth proportional to 640.61, 884.09 and 391.88 is: 540.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.61 : 884.09 = 391.88 : x
  2. Step 2: Convert to fraction form
    640.61/884.09 = 391.88/x
  3. Step 3: Cross multiply
    640.61x = 884.09 × 391.88
  4. Step 4: Simplify right side
    640.61x = 346,457.19
  5. Step 5: Solve for x
    x = 346,457.19/640.61
  6. Step 6: Final answer
    x = 540.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.