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Finding the Fourth Proportional to 103.85, 155.97 and 91.70

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Solution

The fourth proportional to 103.85, 155.97 and 91.70 is: 137.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.85 : 155.97 = 91.70 : x
  2. Step 2: Convert to fraction form
    103.85/155.97 = 91.70/x
  3. Step 3: Cross multiply
    103.85x = 155.97 × 91.70
  4. Step 4: Simplify right side
    103.85x = 14,301.67
  5. Step 5: Solve for x
    x = 14,301.67/103.85
  6. Step 6: Final answer
    x = 137.72

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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.