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Finding the Fourth Proportional to 1,309.28, 1,806.81 and 811.79

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Solution

The fourth proportional to 1,309.28, 1,806.81 and 811.79 is: 1,120.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,309.28 : 1,806.81 = 811.79 : x
  2. Step 2: Convert to fraction form
    1,309.28/1,806.81 = 811.79/x
  3. Step 3: Cross multiply
    1,309.28x = 1,806.81 × 811.79
  4. Step 4: Simplify right side
    1,309.28x = 1,466,750.29
  5. Step 5: Solve for x
    x = 1,466,750.29/1,309.28
  6. Step 6: Final answer
    x = 1,120.27

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.