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Finding the Fourth Proportional to 981.85, 1,355.82 and 668.28

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Solution

The fourth proportional to 981.85, 1,355.82 and 668.28 is: 922.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.85 : 1,355.82 = 668.28 : x
  2. Step 2: Convert to fraction form
    981.85/1,355.82 = 668.28/x
  3. Step 3: Cross multiply
    981.85x = 1,355.82 × 668.28
  4. Step 4: Simplify right side
    981.85x = 906,067.39
  5. Step 5: Solve for x
    x = 906,067.39/981.85
  6. Step 6: Final answer
    x = 922.82

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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.