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Finding the Fourth Proportional to 142.78, 197.10 and 87.56

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Solution

The fourth proportional to 142.78, 197.10 and 87.56 is: 120.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.78 : 197.10 = 87.56 : x
  2. Step 2: Convert to fraction form
    142.78/197.10 = 87.56/x
  3. Step 3: Cross multiply
    142.78x = 197.10 × 87.56
  4. Step 4: Simplify right side
    142.78x = 17,258.08
  5. Step 5: Solve for x
    x = 17,258.08/142.78
  6. Step 6: Final answer
    x = 120.87

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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.