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Finding the Fourth Proportional to 129.08, 178.08 and 89.76

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Solution

The fourth proportional to 129.08, 178.08 and 89.76 is: 123.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.08 : 178.08 = 89.76 : x
  2. Step 2: Convert to fraction form
    129.08/178.08 = 89.76/x
  3. Step 3: Cross multiply
    129.08x = 178.08 × 89.76
  4. Step 4: Simplify right side
    129.08x = 15,984.46
  5. Step 5: Solve for x
    x = 15,984.46/129.08
  6. Step 6: Final answer
    x = 123.83

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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.