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Finding the Fourth Proportional to 1,239.84, 1,711 and 680.30

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Solution

The fourth proportional to 1,239.84, 1,711 and 680.30 is: 938.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.84 : 1,711 = 680.30 : x
  2. Step 2: Convert to fraction form
    1,239.84/1,711 = 680.30/x
  3. Step 3: Cross multiply
    1,239.84x = 1,711 × 680.30
  4. Step 4: Simplify right side
    1,239.84x = 1,163,993.30
  5. Step 5: Solve for x
    x = 1,163,993.30/1,239.84
  6. Step 6: Final answer
    x = 938.83

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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.