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Finding the Fourth Proportional to 401.28, 551.84 and 389.12

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Solution

The fourth proportional to 401.28, 551.84 and 389.12 is: 535.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    401.28 : 551.84 = 389.12 : x
  2. Step 2: Convert to fraction form
    401.28/551.84 = 389.12/x
  3. Step 3: Cross multiply
    401.28x = 551.84 × 389.12
  4. Step 4: Simplify right side
    401.28x = 214,731.98
  5. Step 5: Solve for x
    x = 214,731.98/401.28
  6. Step 6: Final answer
    x = 535.12

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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.