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Finding the Fourth Proportional to 77.76, 116.72 and 67.20

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Solution

The fourth proportional to 77.76, 116.72 and 67.20 is: 100.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.76 : 116.72 = 67.20 : x
  2. Step 2: Convert to fraction form
    77.76/116.72 = 67.20/x
  3. Step 3: Cross multiply
    77.76x = 116.72 × 67.20
  4. Step 4: Simplify right side
    77.76x = 7,843.58
  5. Step 5: Solve for x
    x = 7,843.58/77.76
  6. Step 6: Final answer
    x = 100.87

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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.