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Finding the Fourth Proportional to 81.40, 112.26 and 56.84

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Solution

The fourth proportional to 81.40, 112.26 and 56.84 is: 78.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.40 : 112.26 = 56.84 : x
  2. Step 2: Convert to fraction form
    81.40/112.26 = 56.84/x
  3. Step 3: Cross multiply
    81.40x = 112.26 × 56.84
  4. Step 4: Simplify right side
    81.40x = 6,380.86
  5. Step 5: Solve for x
    x = 6,380.86/81.40
  6. Step 6: Final answer
    x = 78.39

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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.