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Finding the Fourth Proportional to 980.40, 1,470.57 and 287.09

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Solution

The fourth proportional to 980.40, 1,470.57 and 287.09 is: 430.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.40 : 1,470.57 = 287.09 : x
  2. Step 2: Convert to fraction form
    980.40/1,470.57 = 287.09/x
  3. Step 3: Cross multiply
    980.40x = 1,470.57 × 287.09
  4. Step 4: Simplify right side
    980.40x = 422,191.70
  5. Step 5: Solve for x
    x = 422,191.70/980.40
  6. Step 6: Final answer
    x = 430.63

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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.