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Finding the Fourth Proportional to 306.80, 421.34 and 257.59

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Solution

The fourth proportional to 306.80, 421.34 and 257.59 is: 353.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    306.80 : 421.34 = 257.59 : x
  2. Step 2: Convert to fraction form
    306.80/421.34 = 257.59/x
  3. Step 3: Cross multiply
    306.80x = 421.34 × 257.59
  4. Step 4: Simplify right side
    306.80x = 108,532.97
  5. Step 5: Solve for x
    x = 108,532.97/306.80
  6. Step 6: Final answer
    x = 353.76

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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.