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Finding the Fourth Proportional to 129.57, 178.78 and 74.29

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Solution

The fourth proportional to 129.57, 178.78 and 74.29 is: 102.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.57 : 178.78 = 74.29 : x
  2. Step 2: Convert to fraction form
    129.57/178.78 = 74.29/x
  3. Step 3: Cross multiply
    129.57x = 178.78 × 74.29
  4. Step 4: Simplify right side
    129.57x = 13,281.57
  5. Step 5: Solve for x
    x = 13,281.57/129.57
  6. Step 6: Final answer
    x = 102.50

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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.