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Finding the Fourth Proportional to 309.81, 427.10 and 211.40

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Solution

The fourth proportional to 309.81, 427.10 and 211.40 is: 291.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.81 : 427.10 = 211.40 : x
  2. Step 2: Convert to fraction form
    309.81/427.10 = 211.40/x
  3. Step 3: Cross multiply
    309.81x = 427.10 × 211.40
  4. Step 4: Simplify right side
    309.81x = 90,288.94
  5. Step 5: Solve for x
    x = 90,288.94/309.81
  6. Step 6: Final answer
    x = 291.43

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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.