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Finding the Fourth Proportional to 69.40, 104.72 and 66.72

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Solution

The fourth proportional to 69.40, 104.72 and 66.72 is: 100.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.40 : 104.72 = 66.72 : x
  2. Step 2: Convert to fraction form
    69.40/104.72 = 66.72/x
  3. Step 3: Cross multiply
    69.40x = 104.72 × 66.72
  4. Step 4: Simplify right side
    69.40x = 6,986.92
  5. Step 5: Solve for x
    x = 6,986.92/69.40
  6. Step 6: Final answer
    x = 100.68

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.