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Finding the Fourth Proportional to 81.33, 112.17 and 56.79

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Solution

The fourth proportional to 81.33, 112.17 and 56.79 is: 78.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.33 : 112.17 = 56.79 : x
  2. Step 2: Convert to fraction form
    81.33/112.17 = 56.79/x
  3. Step 3: Cross multiply
    81.33x = 112.17 × 56.79
  4. Step 4: Simplify right side
    81.33x = 6,370.13
  5. Step 5: Solve for x
    x = 6,370.13/81.33
  6. Step 6: Final answer
    x = 78.32

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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.