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Finding the Fourth Proportional to 859.44, 1,289.28 and 311.78

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Solution

The fourth proportional to 859.44, 1,289.28 and 311.78 is: 467.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.44 : 1,289.28 = 311.78 : x
  2. Step 2: Convert to fraction form
    859.44/1,289.28 = 311.78/x
  3. Step 3: Cross multiply
    859.44x = 1,289.28 × 311.78
  4. Step 4: Simplify right side
    859.44x = 401,976.11
  5. Step 5: Solve for x
    x = 401,976.11/859.44
  6. Step 6: Final answer
    x = 467.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.