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Finding the Fourth Proportional to 121.31, 181.61 and 69.80

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Solution

The fourth proportional to 121.31, 181.61 and 69.80 is: 104.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.31 : 181.61 = 69.80 : x
  2. Step 2: Convert to fraction form
    121.31/181.61 = 69.80/x
  3. Step 3: Cross multiply
    121.31x = 181.61 × 69.80
  4. Step 4: Simplify right side
    121.31x = 12,675.38
  5. Step 5: Solve for x
    x = 12,675.38/121.31
  6. Step 6: Final answer
    x = 104.49

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.