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Finding the Fourth Proportional to 206.42, 309.35 and 90.89

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Solution

The fourth proportional to 206.42, 309.35 and 90.89 is: 136.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.42 : 309.35 = 90.89 : x
  2. Step 2: Convert to fraction form
    206.42/309.35 = 90.89/x
  3. Step 3: Cross multiply
    206.42x = 309.35 × 90.89
  4. Step 4: Simplify right side
    206.42x = 28,116.66
  5. Step 5: Solve for x
    x = 28,116.66/206.42
  6. Step 6: Final answer
    x = 136.21

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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.