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Finding the Fourth Proportional to 108.75, 163.28 and 86.17

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Solution

The fourth proportional to 108.75, 163.28 and 86.17 is: 129.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.75 : 163.28 = 86.17 : x
  2. Step 2: Convert to fraction form
    108.75/163.28 = 86.17/x
  3. Step 3: Cross multiply
    108.75x = 163.28 × 86.17
  4. Step 4: Simplify right side
    108.75x = 14,069.84
  5. Step 5: Solve for x
    x = 14,069.84/108.75
  6. Step 6: Final answer
    x = 129.38

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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.