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Finding the Fourth Proportional to 611.85, 844.38 and 390.78

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Solution

The fourth proportional to 611.85, 844.38 and 390.78 is: 539.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.85 : 844.38 = 390.78 : x
  2. Step 2: Convert to fraction form
    611.85/844.38 = 390.78/x
  3. Step 3: Cross multiply
    611.85x = 844.38 × 390.78
  4. Step 4: Simplify right side
    611.85x = 329,966.82
  5. Step 5: Solve for x
    x = 329,966.82/611.85
  6. Step 6: Final answer
    x = 539.29

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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.