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Finding the Fourth Proportional to 84.18, 115.67 and 66.90

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Solution

The fourth proportional to 84.18, 115.67 and 66.90 is: 91.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.18 : 115.67 = 66.90 : x
  2. Step 2: Convert to fraction form
    84.18/115.67 = 66.90/x
  3. Step 3: Cross multiply
    84.18x = 115.67 × 66.90
  4. Step 4: Simplify right side
    84.18x = 7,737.99
  5. Step 5: Solve for x
    x = 7,737.99/84.18
  6. Step 6: Final answer
    x = 91.92

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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.