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Finding the Fourth Proportional to 120.80, 180.20 and 108.64

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Solution

The fourth proportional to 120.80, 180.20 and 108.64 is: 162.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.80 : 180.20 = 108.64 : x
  2. Step 2: Convert to fraction form
    120.80/180.20 = 108.64/x
  3. Step 3: Cross multiply
    120.80x = 180.20 × 108.64
  4. Step 4: Simplify right side
    120.80x = 19,576.93
  5. Step 5: Solve for x
    x = 19,576.93/120.80
  6. Step 6: Final answer
    x = 162.06

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.