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Finding the Fourth Proportional to 61.43, 85.28 and 57.78

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Solution

The fourth proportional to 61.43, 85.28 and 57.78 is: 80.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.43 : 85.28 = 57.78 : x
  2. Step 2: Convert to fraction form
    61.43/85.28 = 57.78/x
  3. Step 3: Cross multiply
    61.43x = 85.28 × 57.78
  4. Step 4: Simplify right side
    61.43x = 4,927.19
  5. Step 5: Solve for x
    x = 4,927.19/61.43
  6. Step 6: Final answer
    x = 80.21

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.