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Finding the Fourth Proportional to 79.82, 109.42 and 78.60

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Solution

The fourth proportional to 79.82, 109.42 and 78.60 is: 107.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.82 : 109.42 = 78.60 : x
  2. Step 2: Convert to fraction form
    79.82/109.42 = 78.60/x
  3. Step 3: Cross multiply
    79.82x = 109.42 × 78.60
  4. Step 4: Simplify right side
    79.82x = 8,600.63
  5. Step 5: Solve for x
    x = 8,600.63/79.82
  6. Step 6: Final answer
    x = 107.75

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.