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Finding the Fourth Proportional to 118.28, 163.28 and 87.20

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Solution

The fourth proportional to 118.28, 163.28 and 87.20 is: 120.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    118.28 : 163.28 = 87.20 : x
  2. Step 2: Convert to fraction form
    118.28/163.28 = 87.20/x
  3. Step 3: Cross multiply
    118.28x = 163.28 × 87.20
  4. Step 4: Simplify right side
    118.28x = 14,238.02
  5. Step 5: Solve for x
    x = 14,238.02/118.28
  6. Step 6: Final answer
    x = 120.38

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.