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Finding the Fourth Proportional to 131.50, 197.26 and 85.78

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Solution

The fourth proportional to 131.50, 197.26 and 85.78 is: 128.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.50 : 197.26 = 85.78 : x
  2. Step 2: Convert to fraction form
    131.50/197.26 = 85.78/x
  3. Step 3: Cross multiply
    131.50x = 197.26 × 85.78
  4. Step 4: Simplify right side
    131.50x = 16,920.96
  5. Step 5: Solve for x
    x = 16,920.96/131.50
  6. Step 6: Final answer
    x = 128.68

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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.