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Finding the Fourth Proportional to 57.78, 86.66 and 20.71

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Solution

The fourth proportional to 57.78, 86.66 and 20.71 is: 31.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.78 : 86.66 = 20.71 : x
  2. Step 2: Convert to fraction form
    57.78/86.66 = 20.71/x
  3. Step 3: Cross multiply
    57.78x = 86.66 × 20.71
  4. Step 4: Simplify right side
    57.78x = 1,795.11
  5. Step 5: Solve for x
    x = 1,795.11/57.78
  6. Step 6: Final answer
    x = 31.07

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.