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Finding the Fourth Proportional to 71.86, 107.82 and 31.36

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Solution

The fourth proportional to 71.86, 107.82 and 31.36 is: 47.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.86 : 107.82 = 31.36 : x
  2. Step 2: Convert to fraction form
    71.86/107.82 = 31.36/x
  3. Step 3: Cross multiply
    71.86x = 107.82 × 31.36
  4. Step 4: Simplify right side
    71.86x = 3,381.24
  5. Step 5: Solve for x
    x = 3,381.24/71.86
  6. Step 6: Final answer
    x = 47.05

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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.