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Finding the Fourth Proportional to 485.38, 728.07 and 389.80

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Solution

The fourth proportional to 485.38, 728.07 and 389.80 is: 584.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.38 : 728.07 = 389.80 : x
  2. Step 2: Convert to fraction form
    485.38/728.07 = 389.80/x
  3. Step 3: Cross multiply
    485.38x = 728.07 × 389.80
  4. Step 4: Simplify right side
    485.38x = 283,801.69
  5. Step 5: Solve for x
    x = 283,801.69/485.38
  6. Step 6: Final answer
    x = 584.70

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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.