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Finding the Fourth Proportional to 121.90, 168.30 and 80.53

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Solution

The fourth proportional to 121.90, 168.30 and 80.53 is: 111.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.90 : 168.30 = 80.53 : x
  2. Step 2: Convert to fraction form
    121.90/168.30 = 80.53/x
  3. Step 3: Cross multiply
    121.90x = 168.30 × 80.53
  4. Step 4: Simplify right side
    121.90x = 13,553.20
  5. Step 5: Solve for x
    x = 13,553.20/121.90
  6. Step 6: Final answer
    x = 111.18

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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.