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Finding the Fourth Proportional to 81.87, 112.86 and 65.49

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Solution

The fourth proportional to 81.87, 112.86 and 65.49 is: 90.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.87 : 112.86 = 65.49 : x
  2. Step 2: Convert to fraction form
    81.87/112.86 = 65.49/x
  3. Step 3: Cross multiply
    81.87x = 112.86 × 65.49
  4. Step 4: Simplify right side
    81.87x = 7,391.20
  5. Step 5: Solve for x
    x = 7,391.20/81.87
  6. Step 6: Final answer
    x = 90.28

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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.