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Finding the Fourth Proportional to 61.92, 85.08 and 57.12

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Solution

The fourth proportional to 61.92, 85.08 and 57.12 is: 78.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.92 : 85.08 = 57.12 : x
  2. Step 2: Convert to fraction form
    61.92/85.08 = 57.12/x
  3. Step 3: Cross multiply
    61.92x = 85.08 × 57.12
  4. Step 4: Simplify right side
    61.92x = 4,859.77
  5. Step 5: Solve for x
    x = 4,859.77/61.92
  6. Step 6: Final answer
    x = 78.48

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.