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Finding the Fourth Proportional to 401.81, 557.09 and 388.31

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Solution

The fourth proportional to 401.81, 557.09 and 388.31 is: 538.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    401.81 : 557.09 = 388.31 : x
  2. Step 2: Convert to fraction form
    401.81/557.09 = 388.31/x
  3. Step 3: Cross multiply
    401.81x = 557.09 × 388.31
  4. Step 4: Simplify right side
    401.81x = 216,320.35
  5. Step 5: Solve for x
    x = 216,320.35/401.81
  6. Step 6: Final answer
    x = 538.37

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.