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Finding the Fourth Proportional to 108.96, 163.20 and 85.20

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Solution

The fourth proportional to 108.96, 163.20 and 85.20 is: 127.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.96 : 163.20 = 85.20 : x
  2. Step 2: Convert to fraction form
    108.96/163.20 = 85.20/x
  3. Step 3: Cross multiply
    108.96x = 163.20 × 85.20
  4. Step 4: Simplify right side
    108.96x = 13,904.64
  5. Step 5: Solve for x
    x = 13,904.64/108.96
  6. Step 6: Final answer
    x = 127.61

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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.