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Finding the Fourth Proportional to 85.44, 117.72 and 81.18

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Solution

The fourth proportional to 85.44, 117.72 and 81.18 is: 111.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.44 : 117.72 = 81.18 : x
  2. Step 2: Convert to fraction form
    85.44/117.72 = 81.18/x
  3. Step 3: Cross multiply
    85.44x = 117.72 × 81.18
  4. Step 4: Simplify right side
    85.44x = 9,556.51
  5. Step 5: Solve for x
    x = 9,556.51/85.44
  6. Step 6: Final answer
    x = 111.85

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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.