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Finding the Fourth Proportional to 680.31, 938.92 and 661.78

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Solution

The fourth proportional to 680.31, 938.92 and 661.78 is: 913.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.31 : 938.92 = 661.78 : x
  2. Step 2: Convert to fraction form
    680.31/938.92 = 661.78/x
  3. Step 3: Cross multiply
    680.31x = 938.92 × 661.78
  4. Step 4: Simplify right side
    680.31x = 621,354.48
  5. Step 5: Solve for x
    x = 621,354.48/680.31
  6. Step 6: Final answer
    x = 913.34

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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.