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Finding the Fourth Proportional to 40.90, 61.41 and 31.87

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Solution

The fourth proportional to 40.90, 61.41 and 31.87 is: 47.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.90 : 61.41 = 31.87 : x
  2. Step 2: Convert to fraction form
    40.90/61.41 = 31.87/x
  3. Step 3: Cross multiply
    40.90x = 61.41 × 31.87
  4. Step 4: Simplify right side
    40.90x = 1,957.14
  5. Step 5: Solve for x
    x = 1,957.14/40.90
  6. Step 6: Final answer
    x = 47.85

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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.