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Finding the Fourth Proportional to 971.40, 1,456.20 and 321.78

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Solution

The fourth proportional to 971.40, 1,456.20 and 321.78 is: 482.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    971.40 : 1,456.20 = 321.78 : x
  2. Step 2: Convert to fraction form
    971.40/1,456.20 = 321.78/x
  3. Step 3: Cross multiply
    971.40x = 1,456.20 × 321.78
  4. Step 4: Simplify right side
    971.40x = 468,576.04
  5. Step 5: Solve for x
    x = 468,576.04/971.40
  6. Step 6: Final answer
    x = 482.37

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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.