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Finding the Fourth Proportional to 123.89, 172.16 and 122.65

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Solution

The fourth proportional to 123.89, 172.16 and 122.65 is: 170.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.89 : 172.16 = 122.65 : x
  2. Step 2: Convert to fraction form
    123.89/172.16 = 122.65/x
  3. Step 3: Cross multiply
    123.89x = 172.16 × 122.65
  4. Step 4: Simplify right side
    123.89x = 21,114.56
  5. Step 5: Solve for x
    x = 21,114.56/123.89
  6. Step 6: Final answer
    x = 170.43

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.