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Finding the Fourth Proportional to 859.57, 1,289.90 and 311.70

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Solution

The fourth proportional to 859.57, 1,289.90 and 311.70 is: 467.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.57 : 1,289.90 = 311.70 : x
  2. Step 2: Convert to fraction form
    859.57/1,289.90 = 311.70/x
  3. Step 3: Cross multiply
    859.57x = 1,289.90 × 311.70
  4. Step 4: Simplify right side
    859.57x = 402,062.61
  5. Step 5: Solve for x
    x = 402,062.61/859.57
  6. Step 6: Final answer
    x = 467.75

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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.