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Finding the Fourth Proportional to 153.96, 212.61 and 121.15

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Solution

The fourth proportional to 153.96, 212.61 and 121.15 is: 167.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.96 : 212.61 = 121.15 : x
  2. Step 2: Convert to fraction form
    153.96/212.61 = 121.15/x
  3. Step 3: Cross multiply
    153.96x = 212.61 × 121.15
  4. Step 4: Simplify right side
    153.96x = 25,757.70
  5. Step 5: Solve for x
    x = 25,757.70/153.96
  6. Step 6: Final answer
    x = 167.31

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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.