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Finding the Fourth Proportional to 212.20, 292.86 and 129.28

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Solution

The fourth proportional to 212.20, 292.86 and 129.28 is: 178.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.20 : 292.86 = 129.28 : x
  2. Step 2: Convert to fraction form
    212.20/292.86 = 129.28/x
  3. Step 3: Cross multiply
    212.20x = 292.86 × 129.28
  4. Step 4: Simplify right side
    212.20x = 37,860.94
  5. Step 5: Solve for x
    x = 37,860.94/212.20
  6. Step 6: Final answer
    x = 178.42

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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.