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Finding the Fourth Proportional to 320.40, 442.20 and 189.42

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Solution

The fourth proportional to 320.40, 442.20 and 189.42 is: 261.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.40 : 442.20 = 189.42 : x
  2. Step 2: Convert to fraction form
    320.40/442.20 = 189.42/x
  3. Step 3: Cross multiply
    320.40x = 442.20 × 189.42
  4. Step 4: Simplify right side
    320.40x = 83,761.52
  5. Step 5: Solve for x
    x = 83,761.52/320.40
  6. Step 6: Final answer
    x = 261.43

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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.