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Finding the Fourth Proportional to 61.56, 84.87 and 39.72

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Solution

The fourth proportional to 61.56, 84.87 and 39.72 is: 54.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.56 : 84.87 = 39.72 : x
  2. Step 2: Convert to fraction form
    61.56/84.87 = 39.72/x
  3. Step 3: Cross multiply
    61.56x = 84.87 × 39.72
  4. Step 4: Simplify right side
    61.56x = 3,371.04
  5. Step 5: Solve for x
    x = 3,371.04/61.56
  6. Step 6: Final answer
    x = 54.76

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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.