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Finding the Fourth Proportional to 987, 1,362.78 and 725.40

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Solution

The fourth proportional to 987, 1,362.78 and 725.40 is: 1,001.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    987 : 1,362.78 = 725.40 : x
  2. Step 2: Convert to fraction form
    987/1,362.78 = 725.40/x
  3. Step 3: Cross multiply
    987x = 1,362.78 × 725.40
  4. Step 4: Simplify right side
    987x = 988,560.61
  5. Step 5: Solve for x
    x = 988,560.61/987
  6. Step 6: Final answer
    x = 1,001.58

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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.