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Finding the Fourth Proportional to 309.61, 427.11 and 211.21

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Solution

The fourth proportional to 309.61, 427.11 and 211.21 is: 291.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.61 : 427.11 = 211.21 : x
  2. Step 2: Convert to fraction form
    309.61/427.11 = 211.21/x
  3. Step 3: Cross multiply
    309.61x = 427.11 × 211.21
  4. Step 4: Simplify right side
    309.61x = 90,209.90
  5. Step 5: Solve for x
    x = 90,209.90/309.61
  6. Step 6: Final answer
    x = 291.37

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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.