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Finding the Fourth Proportional to 209.34, 288.80 and 121.98

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Solution

The fourth proportional to 209.34, 288.80 and 121.98 is: 168.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.34 : 288.80 = 121.98 : x
  2. Step 2: Convert to fraction form
    209.34/288.80 = 121.98/x
  3. Step 3: Cross multiply
    209.34x = 288.80 × 121.98
  4. Step 4: Simplify right side
    209.34x = 35,227.82
  5. Step 5: Solve for x
    x = 35,227.82/209.34
  6. Step 6: Final answer
    x = 168.28

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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.