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Finding the Fourth Proportional to 108.79, 163.81 and 78.56

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Solution

The fourth proportional to 108.79, 163.81 and 78.56 is: 118.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.79 : 163.81 = 78.56 : x
  2. Step 2: Convert to fraction form
    108.79/163.81 = 78.56/x
  3. Step 3: Cross multiply
    108.79x = 163.81 × 78.56
  4. Step 4: Simplify right side
    108.79x = 12,869.13
  5. Step 5: Solve for x
    x = 12,869.13/108.79
  6. Step 6: Final answer
    x = 118.30

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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.