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Finding the Fourth Proportional to 129.28, 178.41 and 100.12

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Solution

The fourth proportional to 129.28, 178.41 and 100.12 is: 138.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.28 : 178.41 = 100.12 : x
  2. Step 2: Convert to fraction form
    129.28/178.41 = 100.12/x
  3. Step 3: Cross multiply
    129.28x = 178.41 × 100.12
  4. Step 4: Simplify right side
    129.28x = 17,862.41
  5. Step 5: Solve for x
    x = 17,862.41/129.28
  6. Step 6: Final answer
    x = 138.17

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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.