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Finding the Fourth Proportional to 123.40, 170.28 and 81.87

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Solution

The fourth proportional to 123.40, 170.28 and 81.87 is: 112.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.40 : 170.28 = 81.87 : x
  2. Step 2: Convert to fraction form
    123.40/170.28 = 81.87/x
  3. Step 3: Cross multiply
    123.40x = 170.28 × 81.87
  4. Step 4: Simplify right side
    123.40x = 13,940.82
  5. Step 5: Solve for x
    x = 13,940.82/123.40
  6. Step 6: Final answer
    x = 112.97

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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.