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Finding the Fourth Proportional to 84.39, 125.90 and 78.32

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Solution

The fourth proportional to 84.39, 125.90 and 78.32 is: 116.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.39 : 125.90 = 78.32 : x
  2. Step 2: Convert to fraction form
    84.39/125.90 = 78.32/x
  3. Step 3: Cross multiply
    84.39x = 125.90 × 78.32
  4. Step 4: Simplify right side
    84.39x = 9,859.47
  5. Step 5: Solve for x
    x = 9,859.47/84.39
  6. Step 6: Final answer
    x = 116.83

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.