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Finding the Fourth Proportional to 1,309.21, 1,806.33 and 811.87

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Solution

The fourth proportional to 1,309.21, 1,806.33 and 811.87 is: 1,120.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,309.21 : 1,806.33 = 811.87 : x
  2. Step 2: Convert to fraction form
    1,309.21/1,806.33 = 811.87/x
  3. Step 3: Cross multiply
    1,309.21x = 1,806.33 × 811.87
  4. Step 4: Simplify right side
    1,309.21x = 1,466,505.14
  5. Step 5: Solve for x
    x = 1,466,505.14/1,309.21
  6. Step 6: Final answer
    x = 1,120.15

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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.