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Finding the Fourth Proportional to 70.38, 104.88 and 66.90

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Solution

The fourth proportional to 70.38, 104.88 and 66.90 is: 99.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.38 : 104.88 = 66.90 : x
  2. Step 2: Convert to fraction form
    70.38/104.88 = 66.90/x
  3. Step 3: Cross multiply
    70.38x = 104.88 × 66.90
  4. Step 4: Simplify right side
    70.38x = 7,016.47
  5. Step 5: Solve for x
    x = 7,016.47/70.38
  6. Step 6: Final answer
    x = 99.69

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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.