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Finding the Fourth Proportional to 840.12, 1,254.51 and 686.35

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Solution

The fourth proportional to 840.12, 1,254.51 and 686.35 is: 1,024.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.12 : 1,254.51 = 686.35 : x
  2. Step 2: Convert to fraction form
    840.12/1,254.51 = 686.35/x
  3. Step 3: Cross multiply
    840.12x = 1,254.51 × 686.35
  4. Step 4: Simplify right side
    840.12x = 861,032.94
  5. Step 5: Solve for x
    x = 861,032.94/840.12
  6. Step 6: Final answer
    x = 1,024.89

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.