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Finding the Fourth Proportional to 132.42, 198.78 and 86.28

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Solution

The fourth proportional to 132.42, 198.78 and 86.28 is: 129.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    132.42 : 198.78 = 86.28 : x
  2. Step 2: Convert to fraction form
    132.42/198.78 = 86.28/x
  3. Step 3: Cross multiply
    132.42x = 198.78 × 86.28
  4. Step 4: Simplify right side
    132.42x = 17,150.74
  5. Step 5: Solve for x
    x = 17,150.74/132.42
  6. Step 6: Final answer
    x = 129.52

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.