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Finding the Fourth Proportional to 609.18, 840.78 and 388.20

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Solution

The fourth proportional to 609.18, 840.78 and 388.20 is: 535.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    609.18 : 840.78 = 388.20 : x
  2. Step 2: Convert to fraction form
    609.18/840.78 = 388.20/x
  3. Step 3: Cross multiply
    609.18x = 840.78 × 388.20
  4. Step 4: Simplify right side
    609.18x = 326,390.80
  5. Step 5: Solve for x
    x = 326,390.80/609.18
  6. Step 6: Final answer
    x = 535.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.