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Finding the Fourth Proportional to 121.31, 180.97 and 117.21

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Solution

The fourth proportional to 121.31, 180.97 and 117.21 is: 174.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.31 : 180.97 = 117.21 : x
  2. Step 2: Convert to fraction form
    121.31/180.97 = 117.21/x
  3. Step 3: Cross multiply
    121.31x = 180.97 × 117.21
  4. Step 4: Simplify right side
    121.31x = 21,211.49
  5. Step 5: Solve for x
    x = 21,211.49/121.31
  6. Step 6: Final answer
    x = 174.85

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.