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Finding the Fourth Proportional to 52.20, 71.85 and 39.87

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Solution

The fourth proportional to 52.20, 71.85 and 39.87 is: 54.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    52.20 : 71.85 = 39.87 : x
  2. Step 2: Convert to fraction form
    52.20/71.85 = 39.87/x
  3. Step 3: Cross multiply
    52.20x = 71.85 × 39.87
  4. Step 4: Simplify right side
    52.20x = 2,864.66
  5. Step 5: Solve for x
    x = 2,864.66/52.20
  6. Step 6: Final answer
    x = 54.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.