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Finding the Fourth Proportional to 84.86, 127.21 and 83.78

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Solution

The fourth proportional to 84.86, 127.21 and 83.78 is: 125.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.86 : 127.21 = 83.78 : x
  2. Step 2: Convert to fraction form
    84.86/127.21 = 83.78/x
  3. Step 3: Cross multiply
    84.86x = 127.21 × 83.78
  4. Step 4: Simplify right side
    84.86x = 10,657.65
  5. Step 5: Solve for x
    x = 10,657.65/84.86
  6. Step 6: Final answer
    x = 125.59

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.