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Finding the Fourth Proportional to 81.36, 112.22 and 56.81

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Solution

The fourth proportional to 81.36, 112.22 and 56.81 is: 78.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.36 : 112.22 = 56.81 : x
  2. Step 2: Convert to fraction form
    81.36/112.22 = 56.81/x
  3. Step 3: Cross multiply
    81.36x = 112.22 × 56.81
  4. Step 4: Simplify right side
    81.36x = 6,374.37
  5. Step 5: Solve for x
    x = 6,374.37/81.36
  6. Step 6: Final answer
    x = 78.35

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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.