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Finding the Fourth Proportional to 980.69, 1,470.69 and 287.15

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Solution

The fourth proportional to 980.69, 1,470.69 and 287.15 is: 430.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.69 : 1,470.69 = 287.15 : x
  2. Step 2: Convert to fraction form
    980.69/1,470.69 = 287.15/x
  3. Step 3: Cross multiply
    980.69x = 1,470.69 × 287.15
  4. Step 4: Simplify right side
    980.69x = 422,301.28
  5. Step 5: Solve for x
    x = 422,301.28/980.69
  6. Step 6: Final answer
    x = 430.62

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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.