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Finding the Fourth Proportional to 69.81, 104.15 and 66.55

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Solution

The fourth proportional to 69.81, 104.15 and 66.55 is: 99.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.81 : 104.15 = 66.55 : x
  2. Step 2: Convert to fraction form
    69.81/104.15 = 66.55/x
  3. Step 3: Cross multiply
    69.81x = 104.15 × 66.55
  4. Step 4: Simplify right side
    69.81x = 6,930.99
  5. Step 5: Solve for x
    x = 6,930.99/69.81
  6. Step 6: Final answer
    x = 99.28

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.