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Finding the Fourth Proportional to 69.81, 96.78 and 66.15

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Solution

The fourth proportional to 69.81, 96.78 and 66.15 is: 91.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.81 : 96.78 = 66.15 : x
  2. Step 2: Convert to fraction form
    69.81/96.78 = 66.15/x
  3. Step 3: Cross multiply
    69.81x = 96.78 × 66.15
  4. Step 4: Simplify right side
    69.81x = 6,402.00
  5. Step 5: Solve for x
    x = 6,402.00/69.81
  6. Step 6: Final answer
    x = 91.71

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.