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Finding the Fourth Proportional to 123.15, 170.02 and 81.77

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Solution

The fourth proportional to 123.15, 170.02 and 81.77 is: 112.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.15 : 170.02 = 81.77 : x
  2. Step 2: Convert to fraction form
    123.15/170.02 = 81.77/x
  3. Step 3: Cross multiply
    123.15x = 170.02 × 81.77
  4. Step 4: Simplify right side
    123.15x = 13,902.87
  5. Step 5: Solve for x
    x = 13,902.87/123.15
  6. Step 6: Final answer
    x = 112.89

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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.