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Finding the Fourth Proportional to 121.11, 180.78 and 111.50

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Solution

The fourth proportional to 121.11, 180.78 and 111.50 is: 166.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.11 : 180.78 = 111.50 : x
  2. Step 2: Convert to fraction form
    121.11/180.78 = 111.50/x
  3. Step 3: Cross multiply
    121.11x = 180.78 × 111.50
  4. Step 4: Simplify right side
    121.11x = 20,156.07
  5. Step 5: Solve for x
    x = 20,156.07/121.11
  6. Step 6: Final answer
    x = 166.43

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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.