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Finding the Fourth Proportional to 131.21, 196.89 and 79.86

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Solution

The fourth proportional to 131.21, 196.89 and 79.86 is: 119.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.21 : 196.89 = 79.86 : x
  2. Step 2: Convert to fraction form
    131.21/196.89 = 79.86/x
  3. Step 3: Cross multiply
    131.21x = 196.89 × 79.86
  4. Step 4: Simplify right side
    131.21x = 15,723.64
  5. Step 5: Solve for x
    x = 15,723.64/131.21
  6. Step 6: Final answer
    x = 119.84

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.