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Finding the Fourth Proportional to 142.78, 196.98 and 87.54

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Solution

The fourth proportional to 142.78, 196.98 and 87.54 is: 120.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.78 : 196.98 = 87.54 : x
  2. Step 2: Convert to fraction form
    142.78/196.98 = 87.54/x
  3. Step 3: Cross multiply
    142.78x = 196.98 × 87.54
  4. Step 4: Simplify right side
    142.78x = 17,242.64
  5. Step 5: Solve for x
    x = 17,242.64/142.78
  6. Step 6: Final answer
    x = 120.76

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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.