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Finding the Fourth Proportional to 78.29, 117.27 and 71.85

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Solution

The fourth proportional to 78.29, 117.27 and 71.85 is: 107.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.29 : 117.27 = 71.85 : x
  2. Step 2: Convert to fraction form
    78.29/117.27 = 71.85/x
  3. Step 3: Cross multiply
    78.29x = 117.27 × 71.85
  4. Step 4: Simplify right side
    78.29x = 8,425.85
  5. Step 5: Solve for x
    x = 8,425.85/78.29
  6. Step 6: Final answer
    x = 107.63

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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.