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Finding the Fourth Proportional to 309.39, 426.38 and 221.91

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Solution

The fourth proportional to 309.39, 426.38 and 221.91 is: 305.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.39 : 426.38 = 221.91 : x
  2. Step 2: Convert to fraction form
    309.39/426.38 = 221.91/x
  3. Step 3: Cross multiply
    309.39x = 426.38 × 221.91
  4. Step 4: Simplify right side
    309.39x = 94,616.88
  5. Step 5: Solve for x
    x = 94,616.88/309.39
  6. Step 6: Final answer
    x = 305.82

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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.