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Finding the Fourth Proportional to 206.89, 309.72 and 115.16

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Solution

The fourth proportional to 206.89, 309.72 and 115.16 is: 172.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.89 : 309.72 = 115.16 : x
  2. Step 2: Convert to fraction form
    206.89/309.72 = 115.16/x
  3. Step 3: Cross multiply
    206.89x = 309.72 × 115.16
  4. Step 4: Simplify right side
    206.89x = 35,666.24
  5. Step 5: Solve for x
    x = 35,666.24/206.89
  6. Step 6: Final answer
    x = 172.39

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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.