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Finding the Fourth Proportional to 1,398.50, 1,929.95 and 769.09

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Solution

The fourth proportional to 1,398.50, 1,929.95 and 769.09 is: 1,061.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398.50 : 1,929.95 = 769.09 : x
  2. Step 2: Convert to fraction form
    1,398.50/1,929.95 = 769.09/x
  3. Step 3: Cross multiply
    1,398.50x = 1,929.95 × 769.09
  4. Step 4: Simplify right side
    1,398.50x = 1,484,306.70
  5. Step 5: Solve for x
    x = 1,484,306.70/1,398.50
  6. Step 6: Final answer
    x = 1,061.36

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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.