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Finding the Fourth Proportional to 1,329.12, 1,990.92 and 779.61

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Solution

The fourth proportional to 1,329.12, 1,990.92 and 779.61 is: 1,167.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,329.12 : 1,990.92 = 779.61 : x
  2. Step 2: Convert to fraction form
    1,329.12/1,990.92 = 779.61/x
  3. Step 3: Cross multiply
    1,329.12x = 1,990.92 × 779.61
  4. Step 4: Simplify right side
    1,329.12x = 1,552,141.14
  5. Step 5: Solve for x
    x = 1,552,141.14/1,329.12
  6. Step 6: Final answer
    x = 1,167.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.