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Finding the Fourth Proportional to 123.74, 170.68 and 81.68

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Solution

The fourth proportional to 123.74, 170.68 and 81.68 is: 112.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.74 : 170.68 = 81.68 : x
  2. Step 2: Convert to fraction form
    123.74/170.68 = 81.68/x
  3. Step 3: Cross multiply
    123.74x = 170.68 × 81.68
  4. Step 4: Simplify right side
    123.74x = 13,940.89
  5. Step 5: Solve for x
    x = 13,940.89/123.74
  6. Step 6: Final answer
    x = 112.66

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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.