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Finding the Fourth Proportional to 84.09, 115.97 and 77.81

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Solution

The fourth proportional to 84.09, 115.97 and 77.81 is: 107.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.09 : 115.97 = 77.81 : x
  2. Step 2: Convert to fraction form
    84.09/115.97 = 77.81/x
  3. Step 3: Cross multiply
    84.09x = 115.97 × 77.81
  4. Step 4: Simplify right side
    84.09x = 9,022.66
  5. Step 5: Solve for x
    x = 9,022.66/84.09
  6. Step 6: Final answer
    x = 107.30

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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.