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Finding the Fourth Proportional to 81.61, 112.57 and 69.31

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Solution

The fourth proportional to 81.61, 112.57 and 69.31 is: 95.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.61 : 112.57 = 69.31 : x
  2. Step 2: Convert to fraction form
    81.61/112.57 = 69.31/x
  3. Step 3: Cross multiply
    81.61x = 112.57 × 69.31
  4. Step 4: Simplify right side
    81.61x = 7,802.23
  5. Step 5: Solve for x
    x = 7,802.23/81.61
  6. Step 6: Final answer
    x = 95.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.