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Finding the Fourth Proportional to 640.31, 883.58 and 391.64

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Solution

The fourth proportional to 640.31, 883.58 and 391.64 is: 540.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.31 : 883.58 = 391.64 : x
  2. Step 2: Convert to fraction form
    640.31/883.58 = 391.64/x
  3. Step 3: Cross multiply
    640.31x = 883.58 × 391.64
  4. Step 4: Simplify right side
    640.31x = 346,038.90
  5. Step 5: Solve for x
    x = 346,038.90/640.31
  6. Step 6: Final answer
    x = 540.43

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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.