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Finding the Fourth Proportional to 311.65, 431.85 and 304.47

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Solution

The fourth proportional to 311.65, 431.85 and 304.47 is: 421.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.65 : 431.85 = 304.47 : x
  2. Step 2: Convert to fraction form
    311.65/431.85 = 304.47/x
  3. Step 3: Cross multiply
    311.65x = 431.85 × 304.47
  4. Step 4: Simplify right side
    311.65x = 131,485.08
  5. Step 5: Solve for x
    x = 131,485.08/311.65
  6. Step 6: Final answer
    x = 421.90

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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.