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Finding the Fourth Proportional to 79.86, 110.15 and 78.66

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Solution

The fourth proportional to 79.86, 110.15 and 78.66 is: 108.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.86 : 110.15 = 78.66 : x
  2. Step 2: Convert to fraction form
    79.86/110.15 = 78.66/x
  3. Step 3: Cross multiply
    79.86x = 110.15 × 78.66
  4. Step 4: Simplify right side
    79.86x = 8,664.40
  5. Step 5: Solve for x
    x = 8,664.40/79.86
  6. Step 6: Final answer
    x = 108.49

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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.