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Finding the Fourth Proportional to 108.36, 149.72 and 86.72

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Solution

The fourth proportional to 108.36, 149.72 and 86.72 is: 119.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.36 : 149.72 = 86.72 : x
  2. Step 2: Convert to fraction form
    108.36/149.72 = 86.72/x
  3. Step 3: Cross multiply
    108.36x = 149.72 × 86.72
  4. Step 4: Simplify right side
    108.36x = 12,982.54
  5. Step 5: Solve for x
    x = 12,982.54/108.36
  6. Step 6: Final answer
    x = 119.81

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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.