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Finding the Fourth Proportional to 211.31, 315.79 and 199.61

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Solution

The fourth proportional to 211.31, 315.79 and 199.61 is: 298.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.31 : 315.79 = 199.61 : x
  2. Step 2: Convert to fraction form
    211.31/315.79 = 199.61/x
  3. Step 3: Cross multiply
    211.31x = 315.79 × 199.61
  4. Step 4: Simplify right side
    211.31x = 63,033.84
  5. Step 5: Solve for x
    x = 63,033.84/211.31
  6. Step 6: Final answer
    x = 298.30

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.