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Finding the Fourth Proportional to 312.94, 431.55 and 211.81

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Solution

The fourth proportional to 312.94, 431.55 and 211.81 is: 292.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.94 : 431.55 = 211.81 : x
  2. Step 2: Convert to fraction form
    312.94/431.55 = 211.81/x
  3. Step 3: Cross multiply
    312.94x = 431.55 × 211.81
  4. Step 4: Simplify right side
    312.94x = 91,406.61
  5. Step 5: Solve for x
    x = 91,406.61/312.94
  6. Step 6: Final answer
    x = 292.09

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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.