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Finding the Fourth Proportional to 987.81, 1,481.54 and 439.89

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Solution

The fourth proportional to 987.81, 1,481.54 and 439.89 is: 659.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.81 : 1,481.54 = 439.89 : x
  2. Step 2: Convert to fraction form
    987.81/1,481.54 = 439.89/x
  3. Step 3: Cross multiply
    987.81x = 1,481.54 × 439.89
  4. Step 4: Simplify right side
    987.81x = 651,712.43
  5. Step 5: Solve for x
    x = 651,712.43/987.81
  6. Step 6: Final answer
    x = 659.75

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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.