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Finding the Fourth Proportional to 1,321.28, 1,979.28 and 801

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Solution

The fourth proportional to 1,321.28, 1,979.28 and 801 is: 1,199.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.28 : 1,979.28 = 801 : x
  2. Step 2: Convert to fraction form
    1,321.28/1,979.28 = 801/x
  3. Step 3: Cross multiply
    1,321.28x = 1,979.28 × 801
  4. Step 4: Simplify right side
    1,321.28x = 1,585,403.28
  5. Step 5: Solve for x
    x = 1,585,403.28/1,321.28
  6. Step 6: Final answer
    x = 1,199.90

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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.