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Finding the Fourth Proportional to 120.40, 166.08 and 85.38

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Solution

The fourth proportional to 120.40, 166.08 and 85.38 is: 117.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.40 : 166.08 = 85.38 : x
  2. Step 2: Convert to fraction form
    120.40/166.08 = 85.38/x
  3. Step 3: Cross multiply
    120.40x = 166.08 × 85.38
  4. Step 4: Simplify right side
    120.40x = 14,179.91
  5. Step 5: Solve for x
    x = 14,179.91/120.40
  6. Step 6: Final answer
    x = 117.77

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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.