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Finding the Fourth Proportional to 208.85, 288.09 and 121.55

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Solution

The fourth proportional to 208.85, 288.09 and 121.55 is: 167.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.85 : 288.09 = 121.55 : x
  2. Step 2: Convert to fraction form
    208.85/288.09 = 121.55/x
  3. Step 3: Cross multiply
    208.85x = 288.09 × 121.55
  4. Step 4: Simplify right side
    208.85x = 35,015.90
  5. Step 5: Solve for x
    x = 35,015.90/208.85
  6. Step 6: Final answer
    x = 167.66

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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.