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Finding the Fourth Proportional to 79.82, 109.68 and 66.86

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Solution

The fourth proportional to 79.82, 109.68 and 66.86 is: 91.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.82 : 109.68 = 66.86 : x
  2. Step 2: Convert to fraction form
    79.82/109.68 = 66.86/x
  3. Step 3: Cross multiply
    79.82x = 109.68 × 66.86
  4. Step 4: Simplify right side
    79.82x = 7,333.20
  5. Step 5: Solve for x
    x = 7,333.20/79.82
  6. Step 6: Final answer
    x = 91.87

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.