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Finding the Fourth Proportional to 108.86, 163.91 and 78.63

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Solution

The fourth proportional to 108.86, 163.91 and 78.63 is: 118.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.86 : 163.91 = 78.63 : x
  2. Step 2: Convert to fraction form
    108.86/163.91 = 78.63/x
  3. Step 3: Cross multiply
    108.86x = 163.91 × 78.63
  4. Step 4: Simplify right side
    108.86x = 12,887.85
  5. Step 5: Solve for x
    x = 12,887.85/108.86
  6. Step 6: Final answer
    x = 118.39

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.