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Finding the Fourth Proportional to 79.92, 109.92 and 66.96

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Solution

The fourth proportional to 79.92, 109.92 and 66.96 is: 92.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.92 : 109.92 = 66.96 : x
  2. Step 2: Convert to fraction form
    79.92/109.92 = 66.96/x
  3. Step 3: Cross multiply
    79.92x = 109.92 × 66.96
  4. Step 4: Simplify right side
    79.92x = 7,360.24
  5. Step 5: Solve for x
    x = 7,360.24/79.92
  6. Step 6: Final answer
    x = 92.10

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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.