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Finding the Fourth Proportional to 123.82, 170.85 and 81.79

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Solution

The fourth proportional to 123.82, 170.85 and 81.79 is: 112.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.82 : 170.85 = 81.79 : x
  2. Step 2: Convert to fraction form
    123.82/170.85 = 81.79/x
  3. Step 3: Cross multiply
    123.82x = 170.85 × 81.79
  4. Step 4: Simplify right side
    123.82x = 13,973.82
  5. Step 5: Solve for x
    x = 13,973.82/123.82
  6. Step 6: Final answer
    x = 112.86

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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.