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Finding the Fourth Proportional to 1,286.80, 1,929.03 and 669.78

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Solution

The fourth proportional to 1,286.80, 1,929.03 and 669.78 is: 1,004.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.80 : 1,929.03 = 669.78 : x
  2. Step 2: Convert to fraction form
    1,286.80/1,929.03 = 669.78/x
  3. Step 3: Cross multiply
    1,286.80x = 1,929.03 × 669.78
  4. Step 4: Simplify right side
    1,286.80x = 1,292,025.71
  5. Step 5: Solve for x
    x = 1,292,025.71/1,286.80
  6. Step 6: Final answer
    x = 1,004.06

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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.