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Finding the Fourth Proportional to 85.26, 117.36 and 78.78

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Solution

The fourth proportional to 85.26, 117.36 and 78.78 is: 108.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.26 : 117.36 = 78.78 : x
  2. Step 2: Convert to fraction form
    85.26/117.36 = 78.78/x
  3. Step 3: Cross multiply
    85.26x = 117.36 × 78.78
  4. Step 4: Simplify right side
    85.26x = 9,245.62
  5. Step 5: Solve for x
    x = 9,245.62/85.26
  6. Step 6: Final answer
    x = 108.44

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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.