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Finding the Fourth Proportional to 152.20, 209.99 and 121.20

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Solution

The fourth proportional to 152.20, 209.99 and 121.20 is: 167.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    152.20 : 209.99 = 121.20 : x
  2. Step 2: Convert to fraction form
    152.20/209.99 = 121.20/x
  3. Step 3: Cross multiply
    152.20x = 209.99 × 121.20
  4. Step 4: Simplify right side
    152.20x = 25,450.30
  5. Step 5: Solve for x
    x = 25,450.30/152.20
  6. Step 6: Final answer
    x = 167.21

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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.