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Finding the Fourth Proportional to 678.71, 1,018.15 and 239.86

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Solution

The fourth proportional to 678.71, 1,018.15 and 239.86 is: 359.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.71 : 1,018.15 = 239.86 : x
  2. Step 2: Convert to fraction form
    678.71/1,018.15 = 239.86/x
  3. Step 3: Cross multiply
    678.71x = 1,018.15 × 239.86
  4. Step 4: Simplify right side
    678.71x = 244,213.46
  5. Step 5: Solve for x
    x = 244,213.46/678.71
  6. Step 6: Final answer
    x = 359.82

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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.