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Finding the Fourth Proportional to 80.40, 110.16 and 78.18

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Solution

The fourth proportional to 80.40, 110.16 and 78.18 is: 107.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.40 : 110.16 = 78.18 : x
  2. Step 2: Convert to fraction form
    80.40/110.16 = 78.18/x
  3. Step 3: Cross multiply
    80.40x = 110.16 × 78.18
  4. Step 4: Simplify right side
    80.40x = 8,612.31
  5. Step 5: Solve for x
    x = 8,612.31/80.40
  6. Step 6: Final answer
    x = 107.12

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.