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Finding the Fourth Proportional to 206.34, 309.65 and 90.86

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Solution

The fourth proportional to 206.34, 309.65 and 90.86 is: 136.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.34 : 309.65 = 90.86 : x
  2. Step 2: Convert to fraction form
    206.34/309.65 = 90.86/x
  3. Step 3: Cross multiply
    206.34x = 309.65 × 90.86
  4. Step 4: Simplify right side
    206.34x = 28,135.80
  5. Step 5: Solve for x
    x = 28,135.80/206.34
  6. Step 6: Final answer
    x = 136.36

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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.