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Finding the Fourth Proportional to 640.54, 883.97 and 391.80

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Solution

The fourth proportional to 640.54, 883.97 and 391.80 is: 540.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.54 : 883.97 = 391.80 : x
  2. Step 2: Convert to fraction form
    640.54/883.97 = 391.80/x
  3. Step 3: Cross multiply
    640.54x = 883.97 × 391.80
  4. Step 4: Simplify right side
    640.54x = 346,339.45
  5. Step 5: Solve for x
    x = 346,339.45/640.54
  6. Step 6: Final answer
    x = 540.70

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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.