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Finding the Fourth Proportional to 321.40, 442.42 and 279.72

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Solution

The fourth proportional to 321.40, 442.42 and 279.72 is: 385.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.40 : 442.42 = 279.72 : x
  2. Step 2: Convert to fraction form
    321.40/442.42 = 279.72/x
  3. Step 3: Cross multiply
    321.40x = 442.42 × 279.72
  4. Step 4: Simplify right side
    321.40x = 123,753.72
  5. Step 5: Solve for x
    x = 123,753.72/321.40
  6. Step 6: Final answer
    x = 385.05

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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.