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Finding the Fourth Proportional to 118.40, 163.48 and 81.64

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Solution

The fourth proportional to 118.40, 163.48 and 81.64 is: 112.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    118.40 : 163.48 = 81.64 : x
  2. Step 2: Convert to fraction form
    118.40/163.48 = 81.64/x
  3. Step 3: Cross multiply
    118.40x = 163.48 × 81.64
  4. Step 4: Simplify right side
    118.40x = 13,346.51
  5. Step 5: Solve for x
    x = 13,346.51/118.40
  6. Step 6: Final answer
    x = 112.72

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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.