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Finding the Fourth Proportional to 79.81, 119.05 and 77.20

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Solution

The fourth proportional to 79.81, 119.05 and 77.20 is: 115.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.81 : 119.05 = 77.20 : x
  2. Step 2: Convert to fraction form
    79.81/119.05 = 77.20/x
  3. Step 3: Cross multiply
    79.81x = 119.05 × 77.20
  4. Step 4: Simplify right side
    79.81x = 9,190.66
  5. Step 5: Solve for x
    x = 9,190.66/79.81
  6. Step 6: Final answer
    x = 115.16

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.