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Finding the Fourth Proportional to 197.40, 272.31 and 123.78

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Solution

The fourth proportional to 197.40, 272.31 and 123.78 is: 170.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    197.40 : 272.31 = 123.78 : x
  2. Step 2: Convert to fraction form
    197.40/272.31 = 123.78/x
  3. Step 3: Cross multiply
    197.40x = 272.31 × 123.78
  4. Step 4: Simplify right side
    197.40x = 33,706.53
  5. Step 5: Solve for x
    x = 33,706.53/197.40
  6. Step 6: Final answer
    x = 170.75

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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.