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Finding the Fourth Proportional to 1,398.79, 1,930.26 and 809.38

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Solution

The fourth proportional to 1,398.79, 1,930.26 and 809.38 is: 1,116.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398.79 : 1,930.26 = 809.38 : x
  2. Step 2: Convert to fraction form
    1,398.79/1,930.26 = 809.38/x
  3. Step 3: Cross multiply
    1,398.79x = 1,930.26 × 809.38
  4. Step 4: Simplify right side
    1,398.79x = 1,562,313.84
  5. Step 5: Solve for x
    x = 1,562,313.84/1,398.79
  6. Step 6: Final answer
    x = 1,116.90

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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.