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Finding the Fourth Proportional to 57.78, 86.34 and 39.72

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Solution

The fourth proportional to 57.78, 86.34 and 39.72 is: 59.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.78 : 86.34 = 39.72 : x
  2. Step 2: Convert to fraction form
    57.78/86.34 = 39.72/x
  3. Step 3: Cross multiply
    57.78x = 86.34 × 39.72
  4. Step 4: Simplify right side
    57.78x = 3,429.42
  5. Step 5: Solve for x
    x = 3,429.42/57.78
  6. Step 6: Final answer
    x = 59.35

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.