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Finding the Fourth Proportional to 81.28, 112.07 and 72.05

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Solution

The fourth proportional to 81.28, 112.07 and 72.05 is: 99.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.28 : 112.07 = 72.05 : x
  2. Step 2: Convert to fraction form
    81.28/112.07 = 72.05/x
  3. Step 3: Cross multiply
    81.28x = 112.07 × 72.05
  4. Step 4: Simplify right side
    81.28x = 8,074.28
  5. Step 5: Solve for x
    x = 8,074.28/81.28
  6. Step 6: Final answer
    x = 99.35

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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.