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Finding the Fourth Proportional to 260.65, 391.04 and 78.05

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Solution

The fourth proportional to 260.65, 391.04 and 78.05 is: 117.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.65 : 391.04 = 78.05 : x
  2. Step 2: Convert to fraction form
    260.65/391.04 = 78.05/x
  3. Step 3: Cross multiply
    260.65x = 391.04 × 78.05
  4. Step 4: Simplify right side
    260.65x = 30,520.67
  5. Step 5: Solve for x
    x = 30,520.67/260.65
  6. Step 6: Final answer
    x = 117.09

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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.