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Finding the Third Proportional to 257.91 and 310.78

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Solution

The third proportional to 257.91 and 310.78 is: 374.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.91 : 310.78 = 310.78 : x
  2. Step 2: Convert to fraction form
    257.91/310.78 = 310.78/x
  3. Step 3: Cross multiply
    257.91x = 310.78 × 310.78
  4. Step 4: Simplify right side
    257.91x = 96,584.99
  5. Step 5: Solve for x
    x = 96,584.99/257.91
  6. Step 6: Final answer
    x = 374.50

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Why These Related Problems?

These problems maintain the same ratio (1.21) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.