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Finding the Fourth Proportional to 210.17, 315.30 and 81.92

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Solution

The fourth proportional to 210.17, 315.30 and 81.92 is: 122.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.17 : 315.30 = 81.92 : x
  2. Step 2: Convert to fraction form
    210.17/315.30 = 81.92/x
  3. Step 3: Cross multiply
    210.17x = 315.30 × 81.92
  4. Step 4: Simplify right side
    210.17x = 25,829.38
  5. Step 5: Solve for x
    x = 25,829.38/210.17
  6. Step 6: Final answer
    x = 122.90

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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.