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Finding the Fourth Proportional to 485.74, 728.61 and 280.54

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Solution

The fourth proportional to 485.74, 728.61 and 280.54 is: 420.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.74 : 728.61 = 280.54 : x
  2. Step 2: Convert to fraction form
    485.74/728.61 = 280.54/x
  3. Step 3: Cross multiply
    485.74x = 728.61 × 280.54
  4. Step 4: Simplify right side
    485.74x = 204,404.25
  5. Step 5: Solve for x
    x = 204,404.25/485.74
  6. Step 6: Final answer
    x = 420.81

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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.