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Finding the Fourth Proportional to 485.28, 728.01 and 138.60

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Solution

The fourth proportional to 485.28, 728.01 and 138.60 is: 207.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.28 : 728.01 = 138.60 : x
  2. Step 2: Convert to fraction form
    485.28/728.01 = 138.60/x
  3. Step 3: Cross multiply
    485.28x = 728.01 × 138.60
  4. Step 4: Simplify right side
    485.28x = 100,902.19
  5. Step 5: Solve for x
    x = 100,902.19/485.28
  6. Step 6: Final answer
    x = 207.93

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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.