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Finding the Fourth Proportional to 109.26, 163.31 and 78.66

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Solution

The fourth proportional to 109.26, 163.31 and 78.66 is: 117.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.26 : 163.31 = 78.66 : x
  2. Step 2: Convert to fraction form
    109.26/163.31 = 78.66/x
  3. Step 3: Cross multiply
    109.26x = 163.31 × 78.66
  4. Step 4: Simplify right side
    109.26x = 12,845.57
  5. Step 5: Solve for x
    x = 12,845.57/109.26
  6. Step 6: Final answer
    x = 117.57

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.