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Finding the Fourth Proportional to 206.16, 309.20 and 77.88

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Solution

The fourth proportional to 206.16, 309.20 and 77.88 is: 116.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.16 : 309.20 = 77.88 : x
  2. Step 2: Convert to fraction form
    206.16/309.20 = 77.88/x
  3. Step 3: Cross multiply
    206.16x = 309.20 × 77.88
  4. Step 4: Simplify right side
    206.16x = 24,079.14
  5. Step 5: Solve for x
    x = 24,079.14/206.16
  6. Step 6: Final answer
    x = 116.80

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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.