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Finding the Fourth Proportional to 104.38, 156.29 and 86.42

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Solution

The fourth proportional to 104.38, 156.29 and 86.42 is: 129.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    104.38 : 156.29 = 86.42 : x
  2. Step 2: Convert to fraction form
    104.38/156.29 = 86.42/x
  3. Step 3: Cross multiply
    104.38x = 156.29 × 86.42
  4. Step 4: Simplify right side
    104.38x = 13,506.54
  5. Step 5: Solve for x
    x = 13,506.54/104.38
  6. Step 6: Final answer
    x = 129.40

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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.