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Finding the Fourth Proportional to 1,986.39, 2,979.10 and 669.80

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Solution

The fourth proportional to 1,986.39, 2,979.10 and 669.80 is: 1,004.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,986.39 : 2,979.10 = 669.80 : x
  2. Step 2: Convert to fraction form
    1,986.39/2,979.10 = 669.80/x
  3. Step 3: Cross multiply
    1,986.39x = 2,979.10 × 669.80
  4. Step 4: Simplify right side
    1,986.39x = 1,995,401.18
  5. Step 5: Solve for x
    x = 1,995,401.18/1,986.39
  6. Step 6: Final answer
    x = 1,004.54

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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.