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Finding the Fourth Proportional to 1,209.99, 1,815.05 and 388.20

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Solution

The fourth proportional to 1,209.99, 1,815.05 and 388.20 is: 582.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.99 : 1,815.05 = 388.20 : x
  2. Step 2: Convert to fraction form
    1,209.99/1,815.05 = 388.20/x
  3. Step 3: Cross multiply
    1,209.99x = 1,815.05 × 388.20
  4. Step 4: Simplify right side
    1,209.99x = 704,602.41
  5. Step 5: Solve for x
    x = 704,602.41/1,209.99
  6. Step 6: Final answer
    x = 582.32

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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.