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Finding the Fourth Proportional to 390.11, 538.36 and 215.48

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Solution

The fourth proportional to 390.11, 538.36 and 215.48 is: 297.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.11 : 538.36 = 215.48 : x
  2. Step 2: Convert to fraction form
    390.11/538.36 = 215.48/x
  3. Step 3: Cross multiply
    390.11x = 538.36 × 215.48
  4. Step 4: Simplify right side
    390.11x = 116,006.62
  5. Step 5: Solve for x
    x = 116,006.62/390.11
  6. Step 6: Final answer
    x = 297.37

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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.