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Finding the Fourth Proportional to 211.87, 292.36 and 138.21

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Solution

The fourth proportional to 211.87, 292.36 and 138.21 is: 190.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.87 : 292.36 = 138.21 : x
  2. Step 2: Convert to fraction form
    211.87/292.36 = 138.21/x
  3. Step 3: Cross multiply
    211.87x = 292.36 × 138.21
  4. Step 4: Simplify right side
    211.87x = 40,405.89
  5. Step 5: Solve for x
    x = 40,405.89/211.87
  6. Step 6: Final answer
    x = 190.71

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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.