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Finding the Fourth Proportional to 83.70, 115.47 and 57.78

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Solution

The fourth proportional to 83.70, 115.47 and 57.78 is: 79.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.70 : 115.47 = 57.78 : x
  2. Step 2: Convert to fraction form
    83.70/115.47 = 57.78/x
  3. Step 3: Cross multiply
    83.70x = 115.47 × 57.78
  4. Step 4: Simplify right side
    83.70x = 6,671.86
  5. Step 5: Solve for x
    x = 6,671.86/83.70
  6. Step 6: Final answer
    x = 79.71

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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.