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Finding the Fourth Proportional to 211.92, 292.31 and 138.21

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Solution

The fourth proportional to 211.92, 292.31 and 138.21 is: 190.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.92 : 292.31 = 138.21 : x
  2. Step 2: Convert to fraction form
    211.92/292.31 = 138.21/x
  3. Step 3: Cross multiply
    211.92x = 292.31 × 138.21
  4. Step 4: Simplify right side
    211.92x = 40,398.90
  5. Step 5: Solve for x
    x = 40,398.90/211.92
  6. Step 6: Final answer
    x = 190.64

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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.