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Finding the Fourth Proportional to 781.56, 1,076.22 and 670.86

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Solution

The fourth proportional to 781.56, 1,076.22 and 670.86 is: 923.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.56 : 1,076.22 = 670.86 : x
  2. Step 2: Convert to fraction form
    781.56/1,076.22 = 670.86/x
  3. Step 3: Cross multiply
    781.56x = 1,076.22 × 670.86
  4. Step 4: Simplify right side
    781.56x = 721,992.95
  5. Step 5: Solve for x
    x = 721,992.95/781.56
  6. Step 6: Final answer
    x = 923.78

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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.