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Finding the Fourth Proportional to 859.12, 1,288.67 and 209.86

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Solution

The fourth proportional to 859.12, 1,288.67 and 209.86 is: 314.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.12 : 1,288.67 = 209.86 : x
  2. Step 2: Convert to fraction form
    859.12/1,288.67 = 209.86/x
  3. Step 3: Cross multiply
    859.12x = 1,288.67 × 209.86
  4. Step 4: Simplify right side
    859.12x = 270,440.29
  5. Step 5: Solve for x
    x = 270,440.29/859.12
  6. Step 6: Final answer
    x = 314.79

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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.