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Finding the Fourth Proportional to 1,236.87, 1,855.31 and 688.91

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Solution

The fourth proportional to 1,236.87, 1,855.31 and 688.91 is: 1,033.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,236.87 : 1,855.31 = 688.91 : x
  2. Step 2: Convert to fraction form
    1,236.87/1,855.31 = 688.91/x
  3. Step 3: Cross multiply
    1,236.87x = 1,855.31 × 688.91
  4. Step 4: Simplify right side
    1,236.87x = 1,278,128.89
  5. Step 5: Solve for x
    x = 1,278,128.89/1,236.87
  6. Step 6: Final answer
    x = 1,033.36

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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.