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Finding the Fourth Proportional to 321.80, 444.12 and 311.72

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Solution

The fourth proportional to 321.80, 444.12 and 311.72 is: 430.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.80 : 444.12 = 311.72 : x
  2. Step 2: Convert to fraction form
    321.80/444.12 = 311.72/x
  3. Step 3: Cross multiply
    321.80x = 444.12 × 311.72
  4. Step 4: Simplify right side
    321.80x = 138,441.09
  5. Step 5: Solve for x
    x = 138,441.09/321.80
  6. Step 6: Final answer
    x = 430.21

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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.