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Finding the Fourth Proportional to 76.92, 115.28 and 66.20

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Solution

The fourth proportional to 76.92, 115.28 and 66.20 is: 99.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.92 : 115.28 = 66.20 : x
  2. Step 2: Convert to fraction form
    76.92/115.28 = 66.20/x
  3. Step 3: Cross multiply
    76.92x = 115.28 × 66.20
  4. Step 4: Simplify right side
    76.92x = 7,631.54
  5. Step 5: Solve for x
    x = 7,631.54/76.92
  6. Step 6: Final answer
    x = 99.21

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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.