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Finding the Fourth Proportional to 81.99, 112.32 and 78.30

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Solution

The fourth proportional to 81.99, 112.32 and 78.30 is: 107.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.99 : 112.32 = 78.30 : x
  2. Step 2: Convert to fraction form
    81.99/112.32 = 78.30/x
  3. Step 3: Cross multiply
    81.99x = 112.32 × 78.30
  4. Step 4: Simplify right side
    81.99x = 8,794.66
  5. Step 5: Solve for x
    x = 8,794.66/81.99
  6. Step 6: Final answer
    x = 107.26

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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.