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Finding the Fourth Proportional to 208.54, 287.78 and 121.22

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Solution

The fourth proportional to 208.54, 287.78 and 121.22 is: 167.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.54 : 287.78 = 121.22 : x
  2. Step 2: Convert to fraction form
    208.54/287.78 = 121.22/x
  3. Step 3: Cross multiply
    208.54x = 287.78 × 121.22
  4. Step 4: Simplify right side
    208.54x = 34,884.69
  5. Step 5: Solve for x
    x = 34,884.69/208.54
  6. Step 6: Final answer
    x = 167.28

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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.