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Finding the Fourth Proportional to 1,208.14, 1,811 and 385.80

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Solution

The fourth proportional to 1,208.14, 1,811 and 385.80 is: 578.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,208.14 : 1,811 = 385.80 : x
  2. Step 2: Convert to fraction form
    1,208.14/1,811 = 385.80/x
  3. Step 3: Cross multiply
    1,208.14x = 1,811 × 385.80
  4. Step 4: Simplify right side
    1,208.14x = 698,683.80
  5. Step 5: Solve for x
    x = 698,683.80/1,208.14
  6. Step 6: Final answer
    x = 578.31

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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.