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Finding the Fourth Proportional to 78.26, 107.91 and 71.78

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Solution

The fourth proportional to 78.26, 107.91 and 71.78 is: 98.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.26 : 107.91 = 71.78 : x
  2. Step 2: Convert to fraction form
    78.26/107.91 = 71.78/x
  3. Step 3: Cross multiply
    78.26x = 107.91 × 71.78
  4. Step 4: Simplify right side
    78.26x = 7,745.24
  5. Step 5: Solve for x
    x = 7,745.24/78.26
  6. Step 6: Final answer
    x = 98.97

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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.