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Finding the Fourth Proportional to 120.12, 165.87 and 87.30

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Solution

The fourth proportional to 120.12, 165.87 and 87.30 is: 120.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.12 : 165.87 = 87.30 : x
  2. Step 2: Convert to fraction form
    120.12/165.87 = 87.30/x
  3. Step 3: Cross multiply
    120.12x = 165.87 × 87.30
  4. Step 4: Simplify right side
    120.12x = 14,480.45
  5. Step 5: Solve for x
    x = 14,480.45/120.12
  6. Step 6: Final answer
    x = 120.55

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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.