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Finding the Fourth Proportional to 609.12, 840.65 and 387.99

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Solution

The fourth proportional to 609.12, 840.65 and 387.99 is: 535.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    609.12 : 840.65 = 387.99 : x
  2. Step 2: Convert to fraction form
    609.12/840.65 = 387.99/x
  3. Step 3: Cross multiply
    609.12x = 840.65 × 387.99
  4. Step 4: Simplify right side
    609.12x = 326,161.85
  5. Step 5: Solve for x
    x = 326,161.85/609.12
  6. Step 6: Final answer
    x = 535.46

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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.