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Finding the Fourth Proportional to 142.24, 212.43 and 128.41

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Solution

The fourth proportional to 142.24, 212.43 and 128.41 is: 191.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.24 : 212.43 = 128.41 : x
  2. Step 2: Convert to fraction form
    142.24/212.43 = 128.41/x
  3. Step 3: Cross multiply
    142.24x = 212.43 × 128.41
  4. Step 4: Simplify right side
    142.24x = 27,278.14
  5. Step 5: Solve for x
    x = 27,278.14/142.24
  6. Step 6: Final answer
    x = 191.78

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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.