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Finding the Fourth Proportional to 47.81, 71.43 and 38.70

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Solution

The fourth proportional to 47.81, 71.43 and 38.70 is: 57.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.81 : 71.43 = 38.70 : x
  2. Step 2: Convert to fraction form
    47.81/71.43 = 38.70/x
  3. Step 3: Cross multiply
    47.81x = 71.43 × 38.70
  4. Step 4: Simplify right side
    47.81x = 2,764.34
  5. Step 5: Solve for x
    x = 2,764.34/47.81
  6. Step 6: Final answer
    x = 57.82

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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.