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Finding the Fourth Proportional to 260.70, 391.11 and 78.09

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Solution

The fourth proportional to 260.70, 391.11 and 78.09 is: 117.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.70 : 391.11 = 78.09 : x
  2. Step 2: Convert to fraction form
    260.70/391.11 = 78.09/x
  3. Step 3: Cross multiply
    260.70x = 391.11 × 78.09
  4. Step 4: Simplify right side
    260.70x = 30,541.78
  5. Step 5: Solve for x
    x = 30,541.78/260.70
  6. Step 6: Final answer
    x = 117.15

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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.