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Finding the Fourth Proportional to 131.78, 197.69 and 66.72

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Solution

The fourth proportional to 131.78, 197.69 and 66.72 is: 100.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.78 : 197.69 = 66.72 : x
  2. Step 2: Convert to fraction form
    131.78/197.69 = 66.72/x
  3. Step 3: Cross multiply
    131.78x = 197.69 × 66.72
  4. Step 4: Simplify right side
    131.78x = 13,190.66
  5. Step 5: Solve for x
    x = 13,190.66/131.78
  6. Step 6: Final answer
    x = 100.10

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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.