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Finding the Fourth Proportional to 207.87, 311.81 and 77.90

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Solution

The fourth proportional to 207.87, 311.81 and 77.90 is: 116.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.87 : 311.81 = 77.90 : x
  2. Step 2: Convert to fraction form
    207.87/311.81 = 77.90/x
  3. Step 3: Cross multiply
    207.87x = 311.81 × 77.90
  4. Step 4: Simplify right side
    207.87x = 24,288.05
  5. Step 5: Solve for x
    x = 24,288.05/207.87
  6. Step 6: Final answer
    x = 116.84

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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.