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Finding the Fourth Proportional to 859.09, 1,287.86 and 311.15

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Solution

The fourth proportional to 859.09, 1,287.86 and 311.15 is: 466.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.09 : 1,287.86 = 311.15 : x
  2. Step 2: Convert to fraction form
    859.09/1,287.86 = 311.15/x
  3. Step 3: Cross multiply
    859.09x = 1,287.86 × 311.15
  4. Step 4: Simplify right side
    859.09x = 400,711.20
  5. Step 5: Solve for x
    x = 400,711.20/859.09
  6. Step 6: Final answer
    x = 466.44

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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.