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Finding the Fourth Proportional to 987.59, 1,481.39 and 439.78

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Solution

The fourth proportional to 987.59, 1,481.39 and 439.78 is: 659.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.59 : 1,481.39 = 439.78 : x
  2. Step 2: Convert to fraction form
    987.59/1,481.39 = 439.78/x
  3. Step 3: Cross multiply
    987.59x = 1,481.39 × 439.78
  4. Step 4: Simplify right side
    987.59x = 651,485.69
  5. Step 5: Solve for x
    x = 651,485.69/987.59
  6. Step 6: Final answer
    x = 659.67

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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.