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Finding the Fourth Proportional to 392.78, 589.30 and 118.90

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Solution

The fourth proportional to 392.78, 589.30 and 118.90 is: 178.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.78 : 589.30 = 118.90 : x
  2. Step 2: Convert to fraction form
    392.78/589.30 = 118.90/x
  3. Step 3: Cross multiply
    392.78x = 589.30 × 118.90
  4. Step 4: Simplify right side
    392.78x = 70,069.98
  5. Step 5: Solve for x
    x = 70,069.98/392.78
  6. Step 6: Final answer
    x = 178.39

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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.