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Finding the Fourth Proportional to 208.11, 287.21 and 120.79

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Solution

The fourth proportional to 208.11, 287.21 and 120.79 is: 166.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.11 : 287.21 = 120.79 : x
  2. Step 2: Convert to fraction form
    208.11/287.21 = 120.79/x
  3. Step 3: Cross multiply
    208.11x = 287.21 × 120.79
  4. Step 4: Simplify right side
    208.11x = 34,692.10
  5. Step 5: Solve for x
    x = 34,692.10/208.11
  6. Step 6: Final answer
    x = 166.70

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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.