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Finding the Fourth Proportional to 259.20, 388.80 and 239.40

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Solution

The fourth proportional to 259.20, 388.80 and 239.40 is: 359.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.20 : 388.80 = 239.40 : x
  2. Step 2: Convert to fraction form
    259.20/388.80 = 239.40/x
  3. Step 3: Cross multiply
    259.20x = 388.80 × 239.40
  4. Step 4: Simplify right side
    259.20x = 93,078.72
  5. Step 5: Solve for x
    x = 93,078.72/259.20
  6. Step 6: Final answer
    x = 359.10

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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.