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Finding the Fourth Proportional to 389.72, 537.81 and 215.07

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Solution

The fourth proportional to 389.72, 537.81 and 215.07 is: 296.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.72 : 537.81 = 215.07 : x
  2. Step 2: Convert to fraction form
    389.72/537.81 = 215.07/x
  3. Step 3: Cross multiply
    389.72x = 537.81 × 215.07
  4. Step 4: Simplify right side
    389.72x = 115,664.11
  5. Step 5: Solve for x
    x = 115,664.11/389.72
  6. Step 6: Final answer
    x = 296.79

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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.