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Finding the Fourth Proportional to 485.39, 728.09 and 120.18

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Solution

The fourth proportional to 485.39, 728.09 and 120.18 is: 180.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.39 : 728.09 = 120.18 : x
  2. Step 2: Convert to fraction form
    485.39/728.09 = 120.18/x
  3. Step 3: Cross multiply
    485.39x = 728.09 × 120.18
  4. Step 4: Simplify right side
    485.39x = 87,504.44
  5. Step 5: Solve for x
    x = 87,504.44/485.39
  6. Step 6: Final answer
    x = 180.28

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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.