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Finding the Fourth Proportional to 120.57, 180.94 and 90.20

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Solution

The fourth proportional to 120.57, 180.94 and 90.20 is: 135.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.57 : 180.94 = 90.20 : x
  2. Step 2: Convert to fraction form
    120.57/180.94 = 90.20/x
  3. Step 3: Cross multiply
    120.57x = 180.94 × 90.20
  4. Step 4: Simplify right side
    120.57x = 16,319.66
  5. Step 5: Solve for x
    x = 16,319.66/120.57
  6. Step 6: Final answer
    x = 135.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.