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Finding the Fourth Proportional to 129.56, 178.80 and 85.98

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Solution

The fourth proportional to 129.56, 178.80 and 85.98 is: 118.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.56 : 178.80 = 85.98 : x
  2. Step 2: Convert to fraction form
    129.56/178.80 = 85.98/x
  3. Step 3: Cross multiply
    129.56x = 178.80 × 85.98
  4. Step 4: Simplify right side
    129.56x = 15,373.22
  5. Step 5: Solve for x
    x = 15,373.22/129.56
  6. Step 6: Final answer
    x = 118.65

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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.