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Finding the Fourth Proportional to 206.78, 310.05 and 91.33

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Solution

The fourth proportional to 206.78, 310.05 and 91.33 is: 136.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.78 : 310.05 = 91.33 : x
  2. Step 2: Convert to fraction form
    206.78/310.05 = 91.33/x
  3. Step 3: Cross multiply
    206.78x = 310.05 × 91.33
  4. Step 4: Simplify right side
    206.78x = 28,316.09
  5. Step 5: Solve for x
    x = 28,316.09/206.78
  6. Step 6: Final answer
    x = 136.94

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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.