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Finding the Fourth Proportional to 120.36, 165.86 and 100.66

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Solution

The fourth proportional to 120.36, 165.86 and 100.66 is: 138.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.36 : 165.86 = 100.66 : x
  2. Step 2: Convert to fraction form
    120.36/165.86 = 100.66/x
  3. Step 3: Cross multiply
    120.36x = 165.86 × 100.66
  4. Step 4: Simplify right side
    120.36x = 16,695.47
  5. Step 5: Solve for x
    x = 16,695.47/120.36
  6. Step 6: Final answer
    x = 138.71

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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.