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Finding the Third Proportional to 256.75 and 398.63

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Solution

The third proportional to 256.75 and 398.63 is: 618.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.75 : 398.63 = 398.63 : x
  2. Step 2: Convert to fraction form
    256.75/398.63 = 398.63/x
  3. Step 3: Cross multiply
    256.75x = 398.63 × 398.63
  4. Step 4: Simplify right side
    256.75x = 158,901.89
  5. Step 5: Solve for x
    x = 158,901.89/256.75
  6. Step 6: Final answer
    x = 618.90

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Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.