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Finding the Fourth Proportional to 120.50, 166.31 and 87.42

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Solution

The fourth proportional to 120.50, 166.31 and 87.42 is: 120.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.50 : 166.31 = 87.42 : x
  2. Step 2: Convert to fraction form
    120.50/166.31 = 87.42/x
  3. Step 3: Cross multiply
    120.50x = 166.31 × 87.42
  4. Step 4: Simplify right side
    120.50x = 14,538.38
  5. Step 5: Solve for x
    x = 14,538.38/120.50
  6. Step 6: Final answer
    x = 120.66

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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.