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Finding the Fourth Proportional to 208.43, 287.70 and 138.55

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Solution

The fourth proportional to 208.43, 287.70 and 138.55 is: 191.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.43 : 287.70 = 138.55 : x
  2. Step 2: Convert to fraction form
    208.43/287.70 = 138.55/x
  3. Step 3: Cross multiply
    208.43x = 287.70 × 138.55
  4. Step 4: Simplify right side
    208.43x = 39,858.70
  5. Step 5: Solve for x
    x = 39,858.70/208.43
  6. Step 6: Final answer
    x = 191.23

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.