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Finding the Fourth Proportional to 108.74, 162.90 and 81.80

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Solution

The fourth proportional to 108.74, 162.90 and 81.80 is: 122.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.74 : 162.90 = 81.80 : x
  2. Step 2: Convert to fraction form
    108.74/162.90 = 81.80/x
  3. Step 3: Cross multiply
    108.74x = 162.90 × 81.80
  4. Step 4: Simplify right side
    108.74x = 13,325.22
  5. Step 5: Solve for x
    x = 13,325.22/108.74
  6. Step 6: Final answer
    x = 122.54

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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.