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Finding the Fourth Proportional to 120.21, 180.31 and 84.16

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Solution

The fourth proportional to 120.21, 180.31 and 84.16 is: 126.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.21 : 180.31 = 84.16 : x
  2. Step 2: Convert to fraction form
    120.21/180.31 = 84.16/x
  3. Step 3: Cross multiply
    120.21x = 180.31 × 84.16
  4. Step 4: Simplify right side
    120.21x = 15,174.89
  5. Step 5: Solve for x
    x = 15,174.89/120.21
  6. Step 6: Final answer
    x = 126.24

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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.