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Finding the Fourth Proportional to 428.30, 591.05 and 231.81

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Solution

The fourth proportional to 428.30, 591.05 and 231.81 is: 319.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.30 : 591.05 = 231.81 : x
  2. Step 2: Convert to fraction form
    428.30/591.05 = 231.81/x
  3. Step 3: Cross multiply
    428.30x = 591.05 × 231.81
  4. Step 4: Simplify right side
    428.30x = 137,010.85
  5. Step 5: Solve for x
    x = 137,010.85/428.30
  6. Step 6: Final answer
    x = 319.90

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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.