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Finding the Fourth Proportional to 92.68, 138.78 and 86.68

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Solution

The fourth proportional to 92.68, 138.78 and 86.68 is: 129.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.68 : 138.78 = 86.68 : x
  2. Step 2: Convert to fraction form
    92.68/138.78 = 86.68/x
  3. Step 3: Cross multiply
    92.68x = 138.78 × 86.68
  4. Step 4: Simplify right side
    92.68x = 12,029.45
  5. Step 5: Solve for x
    x = 12,029.45/92.68
  6. Step 6: Final answer
    x = 129.80

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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.