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Finding the Fourth Proportional to 399.81, 551.55 and 289.11

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Solution

The fourth proportional to 399.81, 551.55 and 289.11 is: 398.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.81 : 551.55 = 289.11 : x
  2. Step 2: Convert to fraction form
    399.81/551.55 = 289.11/x
  3. Step 3: Cross multiply
    399.81x = 551.55 × 289.11
  4. Step 4: Simplify right side
    399.81x = 159,458.62
  5. Step 5: Solve for x
    x = 159,458.62/399.81
  6. Step 6: Final answer
    x = 398.84

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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.