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Finding the Fourth Proportional to 142.20, 211.83 and 129.72

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Solution

The fourth proportional to 142.20, 211.83 and 129.72 is: 193.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.20 : 211.83 = 129.72 : x
  2. Step 2: Convert to fraction form
    142.20/211.83 = 129.72/x
  3. Step 3: Cross multiply
    142.20x = 211.83 × 129.72
  4. Step 4: Simplify right side
    142.20x = 27,478.59
  5. Step 5: Solve for x
    x = 27,478.59/142.20
  6. Step 6: Final answer
    x = 193.24

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.