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Finding the Fourth Proportional to 120.65, 166.50 and 81.32

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Solution

The fourth proportional to 120.65, 166.50 and 81.32 is: 112.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.65 : 166.50 = 81.32 : x
  2. Step 2: Convert to fraction form
    120.65/166.50 = 81.32/x
  3. Step 3: Cross multiply
    120.65x = 166.50 × 81.32
  4. Step 4: Simplify right side
    120.65x = 13,540.20
  5. Step 5: Solve for x
    x = 13,540.20/120.65
  6. Step 6: Final answer
    x = 112.22

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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.