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Finding the Fourth Proportional to 485.78, 728.14 and 321.36

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Solution

The fourth proportional to 485.78, 728.14 and 321.36 is: 481.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.78 : 728.14 = 321.36 : x
  2. Step 2: Convert to fraction form
    485.78/728.14 = 321.36/x
  3. Step 3: Cross multiply
    485.78x = 728.14 × 321.36
  4. Step 4: Simplify right side
    485.78x = 233,995.07
  5. Step 5: Solve for x
    x = 233,995.07/485.78
  6. Step 6: Final answer
    x = 481.69

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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.