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Finding the Fourth Proportional to 324.87, 487.30 and 81.40

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Solution

The fourth proportional to 324.87, 487.30 and 81.40 is: 122.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    324.87 : 487.30 = 81.40 : x
  2. Step 2: Convert to fraction form
    324.87/487.30 = 81.40/x
  3. Step 3: Cross multiply
    324.87x = 487.30 × 81.40
  4. Step 4: Simplify right side
    324.87x = 39,663.78
  5. Step 5: Solve for x
    x = 39,663.78/324.87
  6. Step 6: Final answer
    x = 122.09

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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.