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Finding the Fourth Proportional to 129.69, 178.97 and 71.47

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Solution

The fourth proportional to 129.69, 178.97 and 71.47 is: 98.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.69 : 178.97 = 71.47 : x
  2. Step 2: Convert to fraction form
    129.69/178.97 = 71.47/x
  3. Step 3: Cross multiply
    129.69x = 178.97 × 71.47
  4. Step 4: Simplify right side
    129.69x = 12,790.99
  5. Step 5: Solve for x
    x = 12,790.99/129.69
  6. Step 6: Final answer
    x = 98.63

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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.