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Finding the Fourth Proportional to 305.20, 421.29 and 231.70

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Solution

The fourth proportional to 305.20, 421.29 and 231.70 is: 319.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.20 : 421.29 = 231.70 : x
  2. Step 2: Convert to fraction form
    305.20/421.29 = 231.70/x
  3. Step 3: Cross multiply
    305.20x = 421.29 × 231.70
  4. Step 4: Simplify right side
    305.20x = 97,610.79
  5. Step 5: Solve for x
    x = 97,610.79/305.20
  6. Step 6: Final answer
    x = 319.83

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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.