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Finding the Fourth Proportional to 386.78, 534.30 and 289.73

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Solution

The fourth proportional to 386.78, 534.30 and 289.73 is: 400.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.78 : 534.30 = 289.73 : x
  2. Step 2: Convert to fraction form
    386.78/534.30 = 289.73/x
  3. Step 3: Cross multiply
    386.78x = 534.30 × 289.73
  4. Step 4: Simplify right side
    386.78x = 154,799.98
  5. Step 5: Solve for x
    x = 154,799.98/386.78
  6. Step 6: Final answer
    x = 400.23

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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.