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Finding the Fourth Proportional to 84.16, 115.92 and 77.68

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Solution

The fourth proportional to 84.16, 115.92 and 77.68 is: 106.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.16 : 115.92 = 77.68 : x
  2. Step 2: Convert to fraction form
    84.16/115.92 = 77.68/x
  3. Step 3: Cross multiply
    84.16x = 115.92 × 77.68
  4. Step 4: Simplify right side
    84.16x = 9,004.67
  5. Step 5: Solve for x
    x = 9,004.67/84.16
  6. Step 6: Final answer
    x = 106.99

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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.