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Finding the Fourth Proportional to 80.40, 108.90 and 80.40

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Solution

The fourth proportional to 80.40, 108.90 and 80.40 is: 108.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.40 : 108.90 = 80.40 : x
  2. Step 2: Convert to fraction form
    80.40/108.90 = 80.40/x
  3. Step 3: Cross multiply
    80.40x = 108.90 × 80.40
  4. Step 4: Simplify right side
    80.40x = 8,755.56
  5. Step 5: Solve for x
    x = 8,755.56/80.40
  6. Step 6: Final answer
    x = 108.90

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Why These Related Problems?

These problems maintain the same ratio (1.35) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.