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Finding the Fourth Proportional to 84.50, 115.89 and 74.78

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Solution

The fourth proportional to 84.50, 115.89 and 74.78 is: 102.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.50 : 115.89 = 74.78 : x
  2. Step 2: Convert to fraction form
    84.50/115.89 = 74.78/x
  3. Step 3: Cross multiply
    84.50x = 115.89 × 74.78
  4. Step 4: Simplify right side
    84.50x = 8,666.25
  5. Step 5: Solve for x
    x = 8,666.25/84.50
  6. Step 6: Final answer
    x = 102.56

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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.