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Finding the Fourth Proportional to 78.82, 109.22 and 77.38

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Solution

The fourth proportional to 78.82, 109.22 and 77.38 is: 107.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.82 : 109.22 = 77.38 : x
  2. Step 2: Convert to fraction form
    78.82/109.22 = 77.38/x
  3. Step 3: Cross multiply
    78.82x = 109.22 × 77.38
  4. Step 4: Simplify right side
    78.82x = 8,451.44
  5. Step 5: Solve for x
    x = 8,451.44/78.82
  6. Step 6: Final answer
    x = 107.22

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.