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Finding the Fourth Proportional to 208.90, 288.16 and 121.56

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Solution

The fourth proportional to 208.90, 288.16 and 121.56 is: 167.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.90 : 288.16 = 121.56 : x
  2. Step 2: Convert to fraction form
    208.90/288.16 = 121.56/x
  3. Step 3: Cross multiply
    208.90x = 288.16 × 121.56
  4. Step 4: Simplify right side
    208.90x = 35,028.73
  5. Step 5: Solve for x
    x = 35,028.73/208.90
  6. Step 6: Final answer
    x = 167.68

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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.