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Finding the Fourth Proportional to 305.20, 420.69 and 239.59

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Solution

The fourth proportional to 305.20, 420.69 and 239.59 is: 330.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.20 : 420.69 = 239.59 : x
  2. Step 2: Convert to fraction form
    305.20/420.69 = 239.59/x
  3. Step 3: Cross multiply
    305.20x = 420.69 × 239.59
  4. Step 4: Simplify right side
    305.20x = 100,793.12
  5. Step 5: Solve for x
    x = 100,793.12/305.20
  6. Step 6: Final answer
    x = 330.25

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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.