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Finding the Fourth Proportional to 987.55, 1,481.31 and 257.11

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Solution

The fourth proportional to 987.55, 1,481.31 and 257.11 is: 385.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.55 : 1,481.31 = 257.11 : x
  2. Step 2: Convert to fraction form
    987.55/1,481.31 = 257.11/x
  3. Step 3: Cross multiply
    987.55x = 1,481.31 × 257.11
  4. Step 4: Simplify right side
    987.55x = 380,859.61
  5. Step 5: Solve for x
    x = 380,859.61/987.55
  6. Step 6: Final answer
    x = 385.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.