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Finding the Fourth Proportional to 387.09, 533.30 and 321.39

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Solution

The fourth proportional to 387.09, 533.30 and 321.39 is: 442.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.09 : 533.30 = 321.39 : x
  2. Step 2: Convert to fraction form
    387.09/533.30 = 321.39/x
  3. Step 3: Cross multiply
    387.09x = 533.30 × 321.39
  4. Step 4: Simplify right side
    387.09x = 171,395.68
  5. Step 5: Solve for x
    x = 171,395.68/387.09
  6. Step 6: Final answer
    x = 442.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.