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Finding the Fourth Proportional to 947.97, 1,420.74 and 639.09

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Solution

The fourth proportional to 947.97, 1,420.74 and 639.09 is: 957.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.97 : 1,420.74 = 639.09 : x
  2. Step 2: Convert to fraction form
    947.97/1,420.74 = 639.09/x
  3. Step 3: Cross multiply
    947.97x = 1,420.74 × 639.09
  4. Step 4: Simplify right side
    947.97x = 907,980.73
  5. Step 5: Solve for x
    x = 907,980.73/947.97
  6. Step 6: Final answer
    x = 957.82

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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.