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Finding the Fourth Proportional to 308.38, 421.91 and 307.09

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Solution

The fourth proportional to 308.38, 421.91 and 307.09 is: 420.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    308.38 : 421.91 = 307.09 : x
  2. Step 2: Convert to fraction form
    308.38/421.91 = 307.09/x
  3. Step 3: Cross multiply
    308.38x = 421.91 × 307.09
  4. Step 4: Simplify right side
    308.38x = 129,564.49
  5. Step 5: Solve for x
    x = 129,564.49/308.38
  6. Step 6: Final answer
    x = 420.14

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.