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Finding the Fourth Proportional to 120.30, 165.90 and 102.88

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Solution

The fourth proportional to 120.30, 165.90 and 102.88 is: 141.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.30 : 165.90 = 102.88 : x
  2. Step 2: Convert to fraction form
    120.30/165.90 = 102.88/x
  3. Step 3: Cross multiply
    120.30x = 165.90 × 102.88
  4. Step 4: Simplify right side
    120.30x = 17,067.79
  5. Step 5: Solve for x
    x = 17,067.79/120.30
  6. Step 6: Final answer
    x = 141.88

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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.