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Finding the Fourth Proportional to 84.16, 115.52 and 76.80

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Solution

The fourth proportional to 84.16, 115.52 and 76.80 is: 105.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.16 : 115.52 = 76.80 : x
  2. Step 2: Convert to fraction form
    84.16/115.52 = 76.80/x
  3. Step 3: Cross multiply
    84.16x = 115.52 × 76.80
  4. Step 4: Simplify right side
    84.16x = 8,871.94
  5. Step 5: Solve for x
    x = 8,871.94/84.16
  6. Step 6: Final answer
    x = 105.42

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.