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Finding the Fourth Proportional to 640.30, 883.34 and 391.54

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Solution

The fourth proportional to 640.30, 883.34 and 391.54 is: 540.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.30 : 883.34 = 391.54 : x
  2. Step 2: Convert to fraction form
    640.30/883.34 = 391.54/x
  3. Step 3: Cross multiply
    640.30x = 883.34 × 391.54
  4. Step 4: Simplify right side
    640.30x = 345,860.74
  5. Step 5: Solve for x
    x = 345,860.74/640.30
  6. Step 6: Final answer
    x = 540.16

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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.