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Finding the Fourth Proportional to 77.81, 116.79 and 72.60

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Solution

The fourth proportional to 77.81, 116.79 and 72.60 is: 108.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.81 : 116.79 = 72.60 : x
  2. Step 2: Convert to fraction form
    77.81/116.79 = 72.60/x
  3. Step 3: Cross multiply
    77.81x = 116.79 × 72.60
  4. Step 4: Simplify right side
    77.81x = 8,478.65
  5. Step 5: Solve for x
    x = 8,478.65/77.81
  6. Step 6: Final answer
    x = 108.97

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.