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Finding the Fourth Proportional to 82.79, 113.91 and 72.39

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Solution

The fourth proportional to 82.79, 113.91 and 72.39 is: 99.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.79 : 113.91 = 72.39 : x
  2. Step 2: Convert to fraction form
    82.79/113.91 = 72.39/x
  3. Step 3: Cross multiply
    82.79x = 113.91 × 72.39
  4. Step 4: Simplify right side
    82.79x = 8,245.94
  5. Step 5: Solve for x
    x = 8,245.94/82.79
  6. Step 6: Final answer
    x = 99.60

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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.