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Finding the Fourth Proportional to 206.49, 309.75 and 90.88

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Solution

The fourth proportional to 206.49, 309.75 and 90.88 is: 136.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.49 : 309.75 = 90.88 : x
  2. Step 2: Convert to fraction form
    206.49/309.75 = 90.88/x
  3. Step 3: Cross multiply
    206.49x = 309.75 × 90.88
  4. Step 4: Simplify right side
    206.49x = 28,150.08
  5. Step 5: Solve for x
    x = 28,150.08/206.49
  6. Step 6: Final answer
    x = 136.33

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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.