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Finding the Fourth Proportional to 79.21, 108.86 and 77.05

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Solution

The fourth proportional to 79.21, 108.86 and 77.05 is: 105.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.21 : 108.86 = 77.05 : x
  2. Step 2: Convert to fraction form
    79.21/108.86 = 77.05/x
  3. Step 3: Cross multiply
    79.21x = 108.86 × 77.05
  4. Step 4: Simplify right side
    79.21x = 8,387.66
  5. Step 5: Solve for x
    x = 8,387.66/79.21
  6. Step 6: Final answer
    x = 105.89

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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.