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Finding the Fourth Proportional to 260.79, 391.19 and 78.32

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Solution

The fourth proportional to 260.79, 391.19 and 78.32 is: 117.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.79 : 391.19 = 78.32 : x
  2. Step 2: Convert to fraction form
    260.79/391.19 = 78.32/x
  3. Step 3: Cross multiply
    260.79x = 391.19 × 78.32
  4. Step 4: Simplify right side
    260.79x = 30,636.94
  5. Step 5: Solve for x
    x = 30,636.94/260.79
  6. Step 6: Final answer
    x = 117.48

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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.