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Finding the Fourth Proportional to 485.30, 727.89 and 138.66

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Solution

The fourth proportional to 485.30, 727.89 and 138.66 is: 207.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.30 : 727.89 = 138.66 : x
  2. Step 2: Convert to fraction form
    485.30/727.89 = 138.66/x
  3. Step 3: Cross multiply
    485.30x = 727.89 × 138.66
  4. Step 4: Simplify right side
    485.30x = 100,929.23
  5. Step 5: Solve for x
    x = 100,929.23/485.30
  6. Step 6: Final answer
    x = 207.97

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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.