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Finding the Fourth Proportional to 980.26, 1,470.87 and 431.79

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Solution

The fourth proportional to 980.26, 1,470.87 and 431.79 is: 647.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.26 : 1,470.87 = 431.79 : x
  2. Step 2: Convert to fraction form
    980.26/1,470.87 = 431.79/x
  3. Step 3: Cross multiply
    980.26x = 1,470.87 × 431.79
  4. Step 4: Simplify right side
    980.26x = 635,099.82
  5. Step 5: Solve for x
    x = 635,099.82/980.26
  6. Step 6: Final answer
    x = 647.89

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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.