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Finding the Fourth Proportional to 1,309.81, 1,806.21 and 911.95

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Solution

The fourth proportional to 1,309.81, 1,806.21 and 911.95 is: 1,257.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,309.81 : 1,806.21 = 911.95 : x
  2. Step 2: Convert to fraction form
    1,309.81/1,806.21 = 911.95/x
  3. Step 3: Cross multiply
    1,309.81x = 1,806.21 × 911.95
  4. Step 4: Simplify right side
    1,309.81x = 1,647,173.21
  5. Step 5: Solve for x
    x = 1,647,173.21/1,309.81
  6. Step 6: Final answer
    x = 1,257.57

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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.