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Finding the Fourth Proportional to 123.21, 168.93 and 120.78

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Solution

The fourth proportional to 123.21, 168.93 and 120.78 is: 165.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.21 : 168.93 = 120.78 : x
  2. Step 2: Convert to fraction form
    123.21/168.93 = 120.78/x
  3. Step 3: Cross multiply
    123.21x = 168.93 × 120.78
  4. Step 4: Simplify right side
    123.21x = 20,403.37
  5. Step 5: Solve for x
    x = 20,403.37/123.21
  6. Step 6: Final answer
    x = 165.60

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.