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Finding the Fourth Proportional to 81.90, 122.63 and 70.97

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Solution

The fourth proportional to 81.90, 122.63 and 70.97 is: 106.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.90 : 122.63 = 70.97 : x
  2. Step 2: Convert to fraction form
    81.90/122.63 = 70.97/x
  3. Step 3: Cross multiply
    81.90x = 122.63 × 70.97
  4. Step 4: Simplify right side
    81.90x = 8,702.08
  5. Step 5: Solve for x
    x = 8,702.08/81.90
  6. Step 6: Final answer
    x = 106.25

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.