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Finding the Fourth Proportional to 987.12, 1,481.19 and 439.66

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Solution

The fourth proportional to 987.12, 1,481.19 and 439.66 is: 659.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.12 : 1,481.19 = 439.66 : x
  2. Step 2: Convert to fraction form
    987.12/1,481.19 = 439.66/x
  3. Step 3: Cross multiply
    987.12x = 1,481.19 × 439.66
  4. Step 4: Simplify right side
    987.12x = 651,220.20
  5. Step 5: Solve for x
    x = 651,220.20/987.12
  6. Step 6: Final answer
    x = 659.72

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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.