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Finding the Fourth Proportional to 85.78, 117.70 and 82.54

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Solution

The fourth proportional to 85.78, 117.70 and 82.54 is: 113.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.78 : 117.70 = 82.54 : x
  2. Step 2: Convert to fraction form
    85.78/117.70 = 82.54/x
  3. Step 3: Cross multiply
    85.78x = 117.70 × 82.54
  4. Step 4: Simplify right side
    85.78x = 9,714.96
  5. Step 5: Solve for x
    x = 9,714.96/85.78
  6. Step 6: Final answer
    x = 113.25

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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.