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Finding the Fourth Proportional to 421.21, 580.91 and 281.22

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Solution

The fourth proportional to 421.21, 580.91 and 281.22 is: 387.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.21 : 580.91 = 281.22 : x
  2. Step 2: Convert to fraction form
    421.21/580.91 = 281.22/x
  3. Step 3: Cross multiply
    421.21x = 580.91 × 281.22
  4. Step 4: Simplify right side
    421.21x = 163,359.20
  5. Step 5: Solve for x
    x = 163,359.20/421.21
  6. Step 6: Final answer
    x = 387.83

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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.