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Finding the Fourth Proportional to 1,321.95, 1,979.28 and 669.51

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Solution

The fourth proportional to 1,321.95, 1,979.28 and 669.51 is: 1,002.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.95 : 1,979.28 = 669.51 : x
  2. Step 2: Convert to fraction form
    1,321.95/1,979.28 = 669.51/x
  3. Step 3: Cross multiply
    1,321.95x = 1,979.28 × 669.51
  4. Step 4: Simplify right side
    1,321.95x = 1,325,147.75
  5. Step 5: Solve for x
    x = 1,325,147.75/1,321.95
  6. Step 6: Final answer
    x = 1,002.42

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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.