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Finding the Fourth Proportional to 142.81, 197.08 and 87.58

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Solution

The fourth proportional to 142.81, 197.08 and 87.58 is: 120.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.81 : 197.08 = 87.58 : x
  2. Step 2: Convert to fraction form
    142.81/197.08 = 87.58/x
  3. Step 3: Cross multiply
    142.81x = 197.08 × 87.58
  4. Step 4: Simplify right side
    142.81x = 17,260.42
  5. Step 5: Solve for x
    x = 17,260.42/142.81
  6. Step 6: Final answer
    x = 120.86

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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.