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Finding the Fourth Proportional to 81.79, 112.80 and 63.31

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Solution

The fourth proportional to 81.79, 112.80 and 63.31 is: 87.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.79 : 112.80 = 63.31 : x
  2. Step 2: Convert to fraction form
    81.79/112.80 = 63.31/x
  3. Step 3: Cross multiply
    81.79x = 112.80 × 63.31
  4. Step 4: Simplify right side
    81.79x = 7,141.37
  5. Step 5: Solve for x
    x = 7,141.37/81.79
  6. Step 6: Final answer
    x = 87.31

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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.