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Finding the Fourth Proportional to 47.20, 65.12 and 39.92

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Solution

The fourth proportional to 47.20, 65.12 and 39.92 is: 55.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.20 : 65.12 = 39.92 : x
  2. Step 2: Convert to fraction form
    47.20/65.12 = 39.92/x
  3. Step 3: Cross multiply
    47.20x = 65.12 × 39.92
  4. Step 4: Simplify right side
    47.20x = 2,599.59
  5. Step 5: Solve for x
    x = 2,599.59/47.20
  6. Step 6: Final answer
    x = 55.08

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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.