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Finding the Fourth Proportional to 206.90, 311.40 and 155.80

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Solution

The fourth proportional to 206.90, 311.40 and 155.80 is: 234.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.90 : 311.40 = 155.80 : x
  2. Step 2: Convert to fraction form
    206.90/311.40 = 155.80/x
  3. Step 3: Cross multiply
    206.90x = 311.40 × 155.80
  4. Step 4: Simplify right side
    206.90x = 48,516.12
  5. Step 5: Solve for x
    x = 48,516.12/206.90
  6. Step 6: Final answer
    x = 234.49

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.