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Finding the Fourth Proportional to 421.14, 581.20 and 391.98

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Solution

The fourth proportional to 421.14, 581.20 and 391.98 is: 540.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.14 : 581.20 = 391.98 : x
  2. Step 2: Convert to fraction form
    421.14/581.20 = 391.98/x
  3. Step 3: Cross multiply
    421.14x = 581.20 × 391.98
  4. Step 4: Simplify right side
    421.14x = 227,817.80
  5. Step 5: Solve for x
    x = 227,817.80/421.14
  6. Step 6: Final answer
    x = 540.96

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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.