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Finding the Fourth Proportional to 1,209.98, 1,815.12 and 388.31

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Solution

The fourth proportional to 1,209.98, 1,815.12 and 388.31 is: 582.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.98 : 1,815.12 = 388.31 : x
  2. Step 2: Convert to fraction form
    1,209.98/1,815.12 = 388.31/x
  3. Step 3: Cross multiply
    1,209.98x = 1,815.12 × 388.31
  4. Step 4: Simplify right side
    1,209.98x = 704,829.25
  5. Step 5: Solve for x
    x = 704,829.25/1,209.98
  6. Step 6: Final answer
    x = 582.51

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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.