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Finding the Fourth Proportional to 987.29, 1,481.22 and 431.90

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Solution

The fourth proportional to 987.29, 1,481.22 and 431.90 is: 647.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.29 : 1,481.22 = 431.90 : x
  2. Step 2: Convert to fraction form
    987.29/1,481.22 = 431.90/x
  3. Step 3: Cross multiply
    987.29x = 1,481.22 × 431.90
  4. Step 4: Simplify right side
    987.29x = 639,741.49
  5. Step 5: Solve for x
    x = 639,741.49/987.29
  6. Step 6: Final answer
    x = 647.97

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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.