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Finding the Fourth Proportional to 47.85, 71.42 and 38.80

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Solution

The fourth proportional to 47.85, 71.42 and 38.80 is: 57.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.85 : 71.42 = 38.80 : x
  2. Step 2: Convert to fraction form
    47.85/71.42 = 38.80/x
  3. Step 3: Cross multiply
    47.85x = 71.42 × 38.80
  4. Step 4: Simplify right side
    47.85x = 2,771.10
  5. Step 5: Solve for x
    x = 2,771.10/47.85
  6. Step 6: Final answer
    x = 57.91

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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.