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Finding the Fourth Proportional to 389.97, 538.14 and 215.31

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Solution

The fourth proportional to 389.97, 538.14 and 215.31 is: 297.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.97 : 538.14 = 215.31 : x
  2. Step 2: Convert to fraction form
    389.97/538.14 = 215.31/x
  3. Step 3: Cross multiply
    389.97x = 538.14 × 215.31
  4. Step 4: Simplify right side
    389.97x = 115,866.92
  5. Step 5: Solve for x
    x = 115,866.92/389.97
  6. Step 6: Final answer
    x = 297.12

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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.