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Finding the Fourth Proportional to 321.90, 442.39 and 289.50

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Solution

The fourth proportional to 321.90, 442.39 and 289.50 is: 397.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.90 : 442.39 = 289.50 : x
  2. Step 2: Convert to fraction form
    321.90/442.39 = 289.50/x
  3. Step 3: Cross multiply
    321.90x = 442.39 × 289.50
  4. Step 4: Simplify right side
    321.90x = 128,071.91
  5. Step 5: Solve for x
    x = 128,071.91/321.90
  6. Step 6: Final answer
    x = 397.86

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.