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Finding the Fourth Proportional to 81.70, 112.70 and 57.14

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Solution

The fourth proportional to 81.70, 112.70 and 57.14 is: 78.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.70 : 112.70 = 57.14 : x
  2. Step 2: Convert to fraction form
    81.70/112.70 = 57.14/x
  3. Step 3: Cross multiply
    81.70x = 112.70 × 57.14
  4. Step 4: Simplify right side
    81.70x = 6,439.68
  5. Step 5: Solve for x
    x = 6,439.68/81.70
  6. Step 6: Final answer
    x = 78.82

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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.