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Finding the Fourth Proportional to 259.21, 388.81 and 76.61

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Solution

The fourth proportional to 259.21, 388.81 and 76.61 is: 114.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.21 : 388.81 = 76.61 : x
  2. Step 2: Convert to fraction form
    259.21/388.81 = 76.61/x
  3. Step 3: Cross multiply
    259.21x = 388.81 × 76.61
  4. Step 4: Simplify right side
    259.21x = 29,786.73
  5. Step 5: Solve for x
    x = 29,786.73/259.21
  6. Step 6: Final answer
    x = 114.91

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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.