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Finding the Fourth Proportional to 640.44, 883.85 and 391.70

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Solution

The fourth proportional to 640.44, 883.85 and 391.70 is: 540.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.44 : 883.85 = 391.70 : x
  2. Step 2: Convert to fraction form
    640.44/883.85 = 391.70/x
  3. Step 3: Cross multiply
    640.44x = 883.85 × 391.70
  4. Step 4: Simplify right side
    640.44x = 346,197.67
  5. Step 5: Solve for x
    x = 346,197.67/640.44
  6. Step 6: Final answer
    x = 540.56

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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.