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Finding the Fourth Proportional to 206.16, 309.64 and 129.21

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Solution

The fourth proportional to 206.16, 309.64 and 129.21 is: 194.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.16 : 309.64 = 129.21 : x
  2. Step 2: Convert to fraction form
    206.16/309.64 = 129.21/x
  3. Step 3: Cross multiply
    206.16x = 309.64 × 129.21
  4. Step 4: Simplify right side
    206.16x = 40,008.58
  5. Step 5: Solve for x
    x = 40,008.58/206.16
  6. Step 6: Final answer
    x = 194.07

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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.