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Finding the Fourth Proportional to 90.69, 125.04 and 86.91

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Solution

The fourth proportional to 90.69, 125.04 and 86.91 is: 119.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.69 : 125.04 = 86.91 : x
  2. Step 2: Convert to fraction form
    90.69/125.04 = 86.91/x
  3. Step 3: Cross multiply
    90.69x = 125.04 × 86.91
  4. Step 4: Simplify right side
    90.69x = 10,867.23
  5. Step 5: Solve for x
    x = 10,867.23/90.69
  6. Step 6: Final answer
    x = 119.83

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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.