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Finding the Fourth Proportional to 40.86, 61.20 and 31.20

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Solution

The fourth proportional to 40.86, 61.20 and 31.20 is: 46.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.86 : 61.20 = 31.20 : x
  2. Step 2: Convert to fraction form
    40.86/61.20 = 31.20/x
  3. Step 3: Cross multiply
    40.86x = 61.20 × 31.20
  4. Step 4: Simplify right side
    40.86x = 1,909.44
  5. Step 5: Solve for x
    x = 1,909.44/40.86
  6. Step 6: Final answer
    x = 46.73

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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.