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Finding the Fourth Proportional to 120.54, 180.90 and 66.42

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Solution

The fourth proportional to 120.54, 180.90 and 66.42 is: 99.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.54 : 180.90 = 66.42 : x
  2. Step 2: Convert to fraction form
    120.54/180.90 = 66.42/x
  3. Step 3: Cross multiply
    120.54x = 180.90 × 66.42
  4. Step 4: Simplify right side
    120.54x = 12,015.38
  5. Step 5: Solve for x
    x = 12,015.38/120.54
  6. Step 6: Final answer
    x = 99.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.