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Finding the Fourth Proportional to 83.91, 126.49 and 78.34

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Solution

The fourth proportional to 83.91, 126.49 and 78.34 is: 118.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.91 : 126.49 = 78.34 : x
  2. Step 2: Convert to fraction form
    83.91/126.49 = 78.34/x
  3. Step 3: Cross multiply
    83.91x = 126.49 × 78.34
  4. Step 4: Simplify right side
    83.91x = 9,909.23
  5. Step 5: Solve for x
    x = 9,909.23/83.91
  6. Step 6: Final answer
    x = 118.09

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.