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Finding the Fourth Proportional to 485.31, 728.01 and 138.63

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Solution

The fourth proportional to 485.31, 728.01 and 138.63 is: 207.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.31 : 728.01 = 138.63 : x
  2. Step 2: Convert to fraction form
    485.31/728.01 = 138.63/x
  3. Step 3: Cross multiply
    485.31x = 728.01 × 138.63
  4. Step 4: Simplify right side
    485.31x = 100,924.03
  5. Step 5: Solve for x
    x = 100,924.03/485.31
  6. Step 6: Final answer
    x = 207.96

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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.