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Finding the Fourth Proportional to 155, 213.70 and 122.20

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Solution

The fourth proportional to 155, 213.70 and 122.20 is: 168.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    155 : 213.70 = 122.20 : x
  2. Step 2: Convert to fraction form
    155/213.70 = 122.20/x
  3. Step 3: Cross multiply
    155x = 213.70 × 122.20
  4. Step 4: Simplify right side
    155x = 26,114.14
  5. Step 5: Solve for x
    x = 26,114.14/155
  6. Step 6: Final answer
    x = 168.48

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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.