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Finding the Fourth Proportional to 309.91, 427.85 and 211.81

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Solution

The fourth proportional to 309.91, 427.85 and 211.81 is: 292.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.91 : 427.85 = 211.81 : x
  2. Step 2: Convert to fraction form
    309.91/427.85 = 211.81/x
  3. Step 3: Cross multiply
    309.91x = 427.85 × 211.81
  4. Step 4: Simplify right side
    309.91x = 90,621.85
  5. Step 5: Solve for x
    x = 90,621.85/309.91
  6. Step 6: Final answer
    x = 292.41

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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.