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Finding the Fourth Proportional to 81.23, 112.16 and 65.81

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Solution

The fourth proportional to 81.23, 112.16 and 65.81 is: 90.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.23 : 112.16 = 65.81 : x
  2. Step 2: Convert to fraction form
    81.23/112.16 = 65.81/x
  3. Step 3: Cross multiply
    81.23x = 112.16 × 65.81
  4. Step 4: Simplify right side
    81.23x = 7,381.69
  5. Step 5: Solve for x
    x = 7,381.69/81.23
  6. Step 6: Final answer
    x = 90.88

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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.