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Finding the Fourth Proportional to 820.85, 1,230.46 and 388.31

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Solution

The fourth proportional to 820.85, 1,230.46 and 388.31 is: 582.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.85 : 1,230.46 = 388.31 : x
  2. Step 2: Convert to fraction form
    820.85/1,230.46 = 388.31/x
  3. Step 3: Cross multiply
    820.85x = 1,230.46 × 388.31
  4. Step 4: Simplify right side
    820.85x = 477,799.92
  5. Step 5: Solve for x
    x = 477,799.92/820.85
  6. Step 6: Final answer
    x = 582.08

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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.