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Finding the Fourth Proportional to 208.68, 287.91 and 121.29

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Solution

The fourth proportional to 208.68, 287.91 and 121.29 is: 167.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.68 : 287.91 = 121.29 : x
  2. Step 2: Convert to fraction form
    208.68/287.91 = 121.29/x
  3. Step 3: Cross multiply
    208.68x = 287.91 × 121.29
  4. Step 4: Simplify right side
    208.68x = 34,920.60
  5. Step 5: Solve for x
    x = 34,920.60/208.68
  6. Step 6: Final answer
    x = 167.34

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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.