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Finding the Fourth Proportional to 81.74, 112.84 and 78.32

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Solution

The fourth proportional to 81.74, 112.84 and 78.32 is: 108.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.74 : 112.84 = 78.32 : x
  2. Step 2: Convert to fraction form
    81.74/112.84 = 78.32/x
  3. Step 3: Cross multiply
    81.74x = 112.84 × 78.32
  4. Step 4: Simplify right side
    81.74x = 8,837.63
  5. Step 5: Solve for x
    x = 8,837.63/81.74
  6. Step 6: Final answer
    x = 108.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.