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Finding the Fourth Proportional to 259.20, 387.09 and 218.61

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Solution

The fourth proportional to 259.20, 387.09 and 218.61 is: 326.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.20 : 387.09 = 218.61 : x
  2. Step 2: Convert to fraction form
    259.20/387.09 = 218.61/x
  3. Step 3: Cross multiply
    259.20x = 387.09 × 218.61
  4. Step 4: Simplify right side
    259.20x = 84,621.74
  5. Step 5: Solve for x
    x = 84,621.74/259.20
  6. Step 6: Final answer
    x = 326.47

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.