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Finding the Fourth Proportional to 123.42, 171.32 and 121.70

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Solution

The fourth proportional to 123.42, 171.32 and 121.70 is: 168.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.42 : 171.32 = 121.70 : x
  2. Step 2: Convert to fraction form
    123.42/171.32 = 121.70/x
  3. Step 3: Cross multiply
    123.42x = 171.32 × 121.70
  4. Step 4: Simplify right side
    123.42x = 20,849.46
  5. Step 5: Solve for x
    x = 20,849.46/123.42
  6. Step 6: Final answer
    x = 168.93

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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.