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Finding the Fourth Proportional to 102.20, 153.42 and 86.12

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Solution

The fourth proportional to 102.20, 153.42 and 86.12 is: 129.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.20 : 153.42 = 86.12 : x
  2. Step 2: Convert to fraction form
    102.20/153.42 = 86.12/x
  3. Step 3: Cross multiply
    102.20x = 153.42 × 86.12
  4. Step 4: Simplify right side
    102.20x = 13,212.53
  5. Step 5: Solve for x
    x = 13,212.53/102.20
  6. Step 6: Final answer
    x = 129.28

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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.