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Finding the Fourth Proportional to 1,986.94, 2,981.78 and 688.41

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Solution

The fourth proportional to 1,986.94, 2,981.78 and 688.41 is: 1,033.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,986.94 : 2,981.78 = 688.41 : x
  2. Step 2: Convert to fraction form
    1,986.94/2,981.78 = 688.41/x
  3. Step 3: Cross multiply
    1,986.94x = 2,981.78 × 688.41
  4. Step 4: Simplify right side
    1,986.94x = 2,052,687.17
  5. Step 5: Solve for x
    x = 2,052,687.17/1,986.94
  6. Step 6: Final answer
    x = 1,033.09

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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.