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Finding the Fourth Proportional to 821.97, 1,235.79 and 660.78

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Solution

The fourth proportional to 821.97, 1,235.79 and 660.78 is: 993.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.97 : 1,235.79 = 660.78 : x
  2. Step 2: Convert to fraction form
    821.97/1,235.79 = 660.78/x
  3. Step 3: Cross multiply
    821.97x = 1,235.79 × 660.78
  4. Step 4: Simplify right side
    821.97x = 816,585.32
  5. Step 5: Solve for x
    x = 816,585.32/821.97
  6. Step 6: Final answer
    x = 993.45

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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.