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Finding the Fourth Proportional to 129.04, 178.09 and 87.56

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Solution

The fourth proportional to 129.04, 178.09 and 87.56 is: 120.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.04 : 178.09 = 87.56 : x
  2. Step 2: Convert to fraction form
    129.04/178.09 = 87.56/x
  3. Step 3: Cross multiply
    129.04x = 178.09 × 87.56
  4. Step 4: Simplify right side
    129.04x = 15,594.20
  5. Step 5: Solve for x
    x = 15,594.20/129.04
  6. Step 6: Final answer
    x = 120.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.