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Finding the Fourth Proportional to 978.85, 1,350.16 and 647.29

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Solution

The fourth proportional to 978.85, 1,350.16 and 647.29 is: 892.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.85 : 1,350.16 = 647.29 : x
  2. Step 2: Convert to fraction form
    978.85/1,350.16 = 647.29/x
  3. Step 3: Cross multiply
    978.85x = 1,350.16 × 647.29
  4. Step 4: Simplify right side
    978.85x = 873,945.07
  5. Step 5: Solve for x
    x = 873,945.07/978.85
  6. Step 6: Final answer
    x = 892.83

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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.