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Finding the Fourth Proportional to 79.21, 109.87 and 76.99

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Solution

The fourth proportional to 79.21, 109.87 and 76.99 is: 106.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.21 : 109.87 = 76.99 : x
  2. Step 2: Convert to fraction form
    79.21/109.87 = 76.99/x
  3. Step 3: Cross multiply
    79.21x = 109.87 × 76.99
  4. Step 4: Simplify right side
    79.21x = 8,458.89
  5. Step 5: Solve for x
    x = 8,458.89/79.21
  6. Step 6: Final answer
    x = 106.79

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.