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Finding the Fourth Proportional to 208.40, 287.55 and 138.59

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Solution

The fourth proportional to 208.40, 287.55 and 138.59 is: 191.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.40 : 287.55 = 138.59 : x
  2. Step 2: Convert to fraction form
    208.40/287.55 = 138.59/x
  3. Step 3: Cross multiply
    208.40x = 287.55 × 138.59
  4. Step 4: Simplify right side
    208.40x = 39,850.12
  5. Step 5: Solve for x
    x = 39,850.12/208.40
  6. Step 6: Final answer
    x = 191.22

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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.