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Finding the Fourth Proportional to 118.72, 163.65 and 79.31

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Solution

The fourth proportional to 118.72, 163.65 and 79.31 is: 109.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    118.72 : 163.65 = 79.31 : x
  2. Step 2: Convert to fraction form
    118.72/163.65 = 79.31/x
  3. Step 3: Cross multiply
    118.72x = 163.65 × 79.31
  4. Step 4: Simplify right side
    118.72x = 12,978.87
  5. Step 5: Solve for x
    x = 12,978.87/118.72
  6. Step 6: Final answer
    x = 109.32

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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.