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Finding the Fourth Proportional to 321.31, 443.51 and 311.05

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Solution

The fourth proportional to 321.31, 443.51 and 311.05 is: 429.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.31 : 443.51 = 311.05 : x
  2. Step 2: Convert to fraction form
    321.31/443.51 = 311.05/x
  3. Step 3: Cross multiply
    321.31x = 443.51 × 311.05
  4. Step 4: Simplify right side
    321.31x = 137,953.79
  5. Step 5: Solve for x
    x = 137,953.79/321.31
  6. Step 6: Final answer
    x = 429.35

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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.