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Finding the Fourth Proportional to 1,399.23, 1,930.78 and 809.65

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Solution

The fourth proportional to 1,399.23, 1,930.78 and 809.65 is: 1,117.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,399.23 : 1,930.78 = 809.65 : x
  2. Step 2: Convert to fraction form
    1,399.23/1,930.78 = 809.65/x
  3. Step 3: Cross multiply
    1,399.23x = 1,930.78 × 809.65
  4. Step 4: Simplify right side
    1,399.23x = 1,563,246.37
  5. Step 5: Solve for x
    x = 1,563,246.37/1,399.23
  6. Step 6: Final answer
    x = 1,117.22

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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.