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Finding the Fourth Proportional to 1,398.69, 1,930.09 and 809.11

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Solution

The fourth proportional to 1,398.69, 1,930.09 and 809.11 is: 1,116.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398.69 : 1,930.09 = 809.11 : x
  2. Step 2: Convert to fraction form
    1,398.69/1,930.09 = 809.11/x
  3. Step 3: Cross multiply
    1,398.69x = 1,930.09 × 809.11
  4. Step 4: Simplify right side
    1,398.69x = 1,561,655.51
  5. Step 5: Solve for x
    x = 1,561,655.51/1,398.69
  6. Step 6: Final answer
    x = 1,116.51

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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.