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Finding the Fourth Proportional to 206.15, 309.14 and 77.81

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Solution

The fourth proportional to 206.15, 309.14 and 77.81 is: 116.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.15 : 309.14 = 77.81 : x
  2. Step 2: Convert to fraction form
    206.15/309.14 = 77.81/x
  3. Step 3: Cross multiply
    206.15x = 309.14 × 77.81
  4. Step 4: Simplify right side
    206.15x = 24,054.86
  5. Step 5: Solve for x
    x = 24,054.86/206.15
  6. Step 6: Final answer
    x = 116.68

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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.