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Finding the Fourth Proportional to 78.25, 107.89 and 71.73

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Solution

The fourth proportional to 78.25, 107.89 and 71.73 is: 98.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.25 : 107.89 = 71.73 : x
  2. Step 2: Convert to fraction form
    78.25/107.89 = 71.73/x
  3. Step 3: Cross multiply
    78.25x = 107.89 × 71.73
  4. Step 4: Simplify right side
    78.25x = 7,738.95
  5. Step 5: Solve for x
    x = 7,738.95/78.25
  6. Step 6: Final answer
    x = 98.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.