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Finding the Fourth Proportional to 1,209.88, 1,815 and 388.18

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Solution

The fourth proportional to 1,209.88, 1,815 and 388.18 is: 582.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.88 : 1,815 = 388.18 : x
  2. Step 2: Convert to fraction form
    1,209.88/1,815 = 388.18/x
  3. Step 3: Cross multiply
    1,209.88x = 1,815 × 388.18
  4. Step 4: Simplify right side
    1,209.88x = 704,546.70
  5. Step 5: Solve for x
    x = 704,546.70/1,209.88
  6. Step 6: Final answer
    x = 582.33

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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.