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Finding the Fourth Proportional to 85.21, 117.71 and 81.16

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Solution

The fourth proportional to 85.21, 117.71 and 81.16 is: 112.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.21 : 117.71 = 81.16 : x
  2. Step 2: Convert to fraction form
    85.21/117.71 = 81.16/x
  3. Step 3: Cross multiply
    85.21x = 117.71 × 81.16
  4. Step 4: Simplify right side
    85.21x = 9,552.94
  5. Step 5: Solve for x
    x = 9,552.94/85.21
  6. Step 6: Final answer
    x = 112.11

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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.