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Finding the Fourth Proportional to 260.81, 391.25 and 78.18

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Solution

The fourth proportional to 260.81, 391.25 and 78.18 is: 117.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.81 : 391.25 = 78.18 : x
  2. Step 2: Convert to fraction form
    260.81/391.25 = 78.18/x
  3. Step 3: Cross multiply
    260.81x = 391.25 × 78.18
  4. Step 4: Simplify right side
    260.81x = 30,588.12
  5. Step 5: Solve for x
    x = 30,588.12/260.81
  6. Step 6: Final answer
    x = 117.28

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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.