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Finding the Fourth Proportional to 321.32, 445.79 and 309.80

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Solution

The fourth proportional to 321.32, 445.79 and 309.80 is: 429.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.32 : 445.79 = 309.80 : x
  2. Step 2: Convert to fraction form
    321.32/445.79 = 309.80/x
  3. Step 3: Cross multiply
    321.32x = 445.79 × 309.80
  4. Step 4: Simplify right side
    321.32x = 138,105.74
  5. Step 5: Solve for x
    x = 138,105.74/321.32
  6. Step 6: Final answer
    x = 429.81

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.