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Finding the Fourth Proportional to 79.78, 119.14 and 78.94

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Solution

The fourth proportional to 79.78, 119.14 and 78.94 is: 117.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.78 : 119.14 = 78.94 : x
  2. Step 2: Convert to fraction form
    79.78/119.14 = 78.94/x
  3. Step 3: Cross multiply
    79.78x = 119.14 × 78.94
  4. Step 4: Simplify right side
    79.78x = 9,404.91
  5. Step 5: Solve for x
    x = 9,404.91/79.78
  6. Step 6: Final answer
    x = 117.89

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.