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Finding the Fourth Proportional to 211.71, 292.14 and 138.21

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Solution

The fourth proportional to 211.71, 292.14 and 138.21 is: 190.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.71 : 292.14 = 138.21 : x
  2. Step 2: Convert to fraction form
    211.71/292.14 = 138.21/x
  3. Step 3: Cross multiply
    211.71x = 292.14 × 138.21
  4. Step 4: Simplify right side
    211.71x = 40,376.67
  5. Step 5: Solve for x
    x = 40,376.67/211.71
  6. Step 6: Final answer
    x = 190.72

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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.