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Finding the Fourth Proportional to 108.78, 163.26 and 91.76

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Solution

The fourth proportional to 108.78, 163.26 and 91.76 is: 137.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.78 : 163.26 = 91.76 : x
  2. Step 2: Convert to fraction form
    108.78/163.26 = 91.76/x
  3. Step 3: Cross multiply
    108.78x = 163.26 × 91.76
  4. Step 4: Simplify right side
    108.78x = 14,980.74
  5. Step 5: Solve for x
    x = 14,980.74/108.78
  6. Step 6: Final answer
    x = 137.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.