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Finding the Fourth Proportional to 120.85, 166.65 and 85.87

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Solution

The fourth proportional to 120.85, 166.65 and 85.87 is: 118.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.85 : 166.65 = 85.87 : x
  2. Step 2: Convert to fraction form
    120.85/166.65 = 85.87/x
  3. Step 3: Cross multiply
    120.85x = 166.65 × 85.87
  4. Step 4: Simplify right side
    120.85x = 14,310.24
  5. Step 5: Solve for x
    x = 14,310.24/120.85
  6. Step 6: Final answer
    x = 118.41

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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.