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Finding the Fourth Proportional to 129.69, 178.95 and 74.42

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Solution

The fourth proportional to 129.69, 178.95 and 74.42 is: 102.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.69 : 178.95 = 74.42 : x
  2. Step 2: Convert to fraction form
    129.69/178.95 = 74.42/x
  3. Step 3: Cross multiply
    129.69x = 178.95 × 74.42
  4. Step 4: Simplify right side
    129.69x = 13,316.19
  5. Step 5: Solve for x
    x = 13,316.19/129.69
  6. Step 6: Final answer
    x = 102.68

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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.