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Finding the Fourth Proportional to 76.28, 105.22 and 66.60

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Solution

The fourth proportional to 76.28, 105.22 and 66.60 is: 91.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.28 : 105.22 = 66.60 : x
  2. Step 2: Convert to fraction form
    76.28/105.22 = 66.60/x
  3. Step 3: Cross multiply
    76.28x = 105.22 × 66.60
  4. Step 4: Simplify right side
    76.28x = 7,007.65
  5. Step 5: Solve for x
    x = 7,007.65/76.28
  6. Step 6: Final answer
    x = 91.87

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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.