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Finding the Fourth Proportional to 90.77, 125.15 and 81.66

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Solution

The fourth proportional to 90.77, 125.15 and 81.66 is: 112.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.77 : 125.15 = 81.66 : x
  2. Step 2: Convert to fraction form
    90.77/125.15 = 81.66/x
  3. Step 3: Cross multiply
    90.77x = 125.15 × 81.66
  4. Step 4: Simplify right side
    90.77x = 10,219.11
  5. Step 5: Solve for x
    x = 10,219.11/90.77
  6. Step 6: Final answer
    x = 112.58

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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.