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Finding the Fourth Proportional to 103.60, 155.21 and 86.59

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Solution

The fourth proportional to 103.60, 155.21 and 86.59 is: 129.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.60 : 155.21 = 86.59 : x
  2. Step 2: Convert to fraction form
    103.60/155.21 = 86.59/x
  3. Step 3: Cross multiply
    103.60x = 155.21 × 86.59
  4. Step 4: Simplify right side
    103.60x = 13,439.63
  5. Step 5: Solve for x
    x = 13,439.63/103.60
  6. Step 6: Final answer
    x = 129.73

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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.