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Finding the Fourth Proportional to 115.21, 172.86 and 109.18

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Solution

The fourth proportional to 115.21, 172.86 and 109.18 is: 163.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.21 : 172.86 = 109.18 : x
  2. Step 2: Convert to fraction form
    115.21/172.86 = 109.18/x
  3. Step 3: Cross multiply
    115.21x = 172.86 × 109.18
  4. Step 4: Simplify right side
    115.21x = 18,872.85
  5. Step 5: Solve for x
    x = 18,872.85/115.21
  6. Step 6: Final answer
    x = 163.81

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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.