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Finding the Fourth Proportional to 421.56, 580.91 and 399.98

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Solution

The fourth proportional to 421.56, 580.91 and 399.98 is: 551.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.56 : 580.91 = 399.98 : x
  2. Step 2: Convert to fraction form
    421.56/580.91 = 399.98/x
  3. Step 3: Cross multiply
    421.56x = 580.91 × 399.98
  4. Step 4: Simplify right side
    421.56x = 232,351.83
  5. Step 5: Solve for x
    x = 232,351.83/421.56
  6. Step 6: Final answer
    x = 551.17

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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.