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Finding the Fourth Proportional to 309.69, 426.87 and 211.28

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Solution

The fourth proportional to 309.69, 426.87 and 211.28 is: 291.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.69 : 426.87 = 211.28 : x
  2. Step 2: Convert to fraction form
    309.69/426.87 = 211.28/x
  3. Step 3: Cross multiply
    309.69x = 426.87 × 211.28
  4. Step 4: Simplify right side
    309.69x = 90,186.96
  5. Step 5: Solve for x
    x = 90,186.96/309.69
  6. Step 6: Final answer
    x = 291.22

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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.