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Finding the Fourth Proportional to 981.91, 1,352.25 and 978.87

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Solution

The fourth proportional to 981.91, 1,352.25 and 978.87 is: 1,348.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.91 : 1,352.25 = 978.87 : x
  2. Step 2: Convert to fraction form
    981.91/1,352.25 = 978.87/x
  3. Step 3: Cross multiply
    981.91x = 1,352.25 × 978.87
  4. Step 4: Simplify right side
    981.91x = 1,323,676.96
  5. Step 5: Solve for x
    x = 1,323,676.96/981.91
  6. Step 6: Final answer
    x = 1,348.06

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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.