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Finding the Fourth Proportional to 84.85, 117.18 and 81.81

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Solution

The fourth proportional to 84.85, 117.18 and 81.81 is: 112.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.85 : 117.18 = 81.81 : x
  2. Step 2: Convert to fraction form
    84.85/117.18 = 81.81/x
  3. Step 3: Cross multiply
    84.85x = 117.18 × 81.81
  4. Step 4: Simplify right side
    84.85x = 9,586.50
  5. Step 5: Solve for x
    x = 9,586.50/84.85
  6. Step 6: Final answer
    x = 112.99

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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.