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Finding the Fourth Proportional to 80.21, 119.82 and 78.69

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Solution

The fourth proportional to 80.21, 119.82 and 78.69 is: 117.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.21 : 119.82 = 78.69 : x
  2. Step 2: Convert to fraction form
    80.21/119.82 = 78.69/x
  3. Step 3: Cross multiply
    80.21x = 119.82 × 78.69
  4. Step 4: Simplify right side
    80.21x = 9,428.64
  5. Step 5: Solve for x
    x = 9,428.64/80.21
  6. Step 6: Final answer
    x = 117.56

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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.