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Finding the Fourth Proportional to 103.86, 155.79 and 31.72

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Solution

The fourth proportional to 103.86, 155.79 and 31.72 is: 47.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.86 : 155.79 = 31.72 : x
  2. Step 2: Convert to fraction form
    103.86/155.79 = 31.72/x
  3. Step 3: Cross multiply
    103.86x = 155.79 × 31.72
  4. Step 4: Simplify right side
    103.86x = 4,941.66
  5. Step 5: Solve for x
    x = 4,941.66/103.86
  6. Step 6: Final answer
    x = 47.58

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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.