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Finding the Fourth Proportional to 1,338.48, 2,006.28 and 687.78

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Solution

The fourth proportional to 1,338.48, 2,006.28 and 687.78 is: 1,030.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,338.48 : 2,006.28 = 687.78 : x
  2. Step 2: Convert to fraction form
    1,338.48/2,006.28 = 687.78/x
  3. Step 3: Cross multiply
    1,338.48x = 2,006.28 × 687.78
  4. Step 4: Simplify right side
    1,338.48x = 1,379,879.26
  5. Step 5: Solve for x
    x = 1,379,879.26/1,338.48
  6. Step 6: Final answer
    x = 1,030.93

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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.