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Finding the Fourth Proportional to 138.15, 206.95 and 121.05

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Solution

The fourth proportional to 138.15, 206.95 and 121.05 is: 181.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.15 : 206.95 = 121.05 : x
  2. Step 2: Convert to fraction form
    138.15/206.95 = 121.05/x
  3. Step 3: Cross multiply
    138.15x = 206.95 × 121.05
  4. Step 4: Simplify right side
    138.15x = 25,051.30
  5. Step 5: Solve for x
    x = 25,051.30/138.15
  6. Step 6: Final answer
    x = 181.33

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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.