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Finding the Fourth Proportional to 206.61, 309.94 and 91.05

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Solution

The fourth proportional to 206.61, 309.94 and 91.05 is: 136.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.61 : 309.94 = 91.05 : x
  2. Step 2: Convert to fraction form
    206.61/309.94 = 91.05/x
  3. Step 3: Cross multiply
    206.61x = 309.94 × 91.05
  4. Step 4: Simplify right side
    206.61x = 28,220.39
  5. Step 5: Solve for x
    x = 28,220.39/206.61
  6. Step 6: Final answer
    x = 136.59

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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.