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Finding the Fourth Proportional to 153.78, 230.40 and 121.15

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Solution

The fourth proportional to 153.78, 230.40 and 121.15 is: 181.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.78 : 230.40 = 121.15 : x
  2. Step 2: Convert to fraction form
    153.78/230.40 = 121.15/x
  3. Step 3: Cross multiply
    153.78x = 230.40 × 121.15
  4. Step 4: Simplify right side
    153.78x = 27,912.96
  5. Step 5: Solve for x
    x = 27,912.96/153.78
  6. Step 6: Final answer
    x = 181.51

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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.