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Finding the Fourth Proportional to 1,318.87, 1,979.39 and 669.79

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Solution

The fourth proportional to 1,318.87, 1,979.39 and 669.79 is: 1,005.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,318.87 : 1,979.39 = 669.79 : x
  2. Step 2: Convert to fraction form
    1,318.87/1,979.39 = 669.79/x
  3. Step 3: Cross multiply
    1,318.87x = 1,979.39 × 669.79
  4. Step 4: Simplify right side
    1,318.87x = 1,325,775.63
  5. Step 5: Solve for x
    x = 1,325,775.63/1,318.87
  6. Step 6: Final answer
    x = 1,005.24

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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.