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Finding the Fourth Proportional to 71.87, 107.80 and 42.57

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Solution

The fourth proportional to 71.87, 107.80 and 42.57 is: 63.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.87 : 107.80 = 42.57 : x
  2. Step 2: Convert to fraction form
    71.87/107.80 = 42.57/x
  3. Step 3: Cross multiply
    71.87x = 107.80 × 42.57
  4. Step 4: Simplify right side
    71.87x = 4,588.94
  5. Step 5: Solve for x
    x = 4,588.94/71.87
  6. Step 6: Final answer
    x = 63.86

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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.