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Finding the Fourth Proportional to 208.86, 288.21 and 121.54

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Solution

The fourth proportional to 208.86, 288.21 and 121.54 is: 167.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.86 : 288.21 = 121.54 : x
  2. Step 2: Convert to fraction form
    208.86/288.21 = 121.54/x
  3. Step 3: Cross multiply
    208.86x = 288.21 × 121.54
  4. Step 4: Simplify right side
    208.86x = 35,029.04
  5. Step 5: Solve for x
    x = 35,029.04/208.86
  6. Step 6: Final answer
    x = 167.72

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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.