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Finding the Fourth Proportional to 889.75, 1,229.46 and 640.66

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Solution

The fourth proportional to 889.75, 1,229.46 and 640.66 is: 885.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    889.75 : 1,229.46 = 640.66 : x
  2. Step 2: Convert to fraction form
    889.75/1,229.46 = 640.66/x
  3. Step 3: Cross multiply
    889.75x = 1,229.46 × 640.66
  4. Step 4: Simplify right side
    889.75x = 787,665.84
  5. Step 5: Solve for x
    x = 787,665.84/889.75
  6. Step 6: Final answer
    x = 885.27

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.