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Finding the Fourth Proportional to 123.80, 169.86 and 121.64

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Solution

The fourth proportional to 123.80, 169.86 and 121.64 is: 166.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.80 : 169.86 = 121.64 : x
  2. Step 2: Convert to fraction form
    123.80/169.86 = 121.64/x
  3. Step 3: Cross multiply
    123.80x = 169.86 × 121.64
  4. Step 4: Simplify right side
    123.80x = 20,661.38
  5. Step 5: Solve for x
    x = 20,661.38/123.80
  6. Step 6: Final answer
    x = 166.90

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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.