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Finding the Fourth Proportional to 311.82, 430.31 and 288.63

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Solution

The fourth proportional to 311.82, 430.31 and 288.63 is: 398.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.82 : 430.31 = 288.63 : x
  2. Step 2: Convert to fraction form
    311.82/430.31 = 288.63/x
  3. Step 3: Cross multiply
    311.82x = 430.31 × 288.63
  4. Step 4: Simplify right side
    311.82x = 124,198.93
  5. Step 5: Solve for x
    x = 124,198.93/311.82
  6. Step 6: Final answer
    x = 398.30

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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.