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Finding the Fourth Proportional to 399.57, 551.91 and 305.74

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Solution

The fourth proportional to 399.57, 551.91 and 305.74 is: 422.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.57 : 551.91 = 305.74 : x
  2. Step 2: Convert to fraction form
    399.57/551.91 = 305.74/x
  3. Step 3: Cross multiply
    399.57x = 551.91 × 305.74
  4. Step 4: Simplify right side
    399.57x = 168,740.96
  5. Step 5: Solve for x
    x = 168,740.96/399.57
  6. Step 6: Final answer
    x = 422.31

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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.