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Finding the Fourth Proportional to 640.41, 883.70 and 391.79

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Solution

The fourth proportional to 640.41, 883.70 and 391.79 is: 540.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.41 : 883.70 = 391.79 : x
  2. Step 2: Convert to fraction form
    640.41/883.70 = 391.79/x
  3. Step 3: Cross multiply
    640.41x = 883.70 × 391.79
  4. Step 4: Simplify right side
    640.41x = 346,224.82
  5. Step 5: Solve for x
    x = 346,224.82/640.41
  6. Step 6: Final answer
    x = 540.63

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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.