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Finding the Third Proportional to 256.50 and 398.25

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Solution

The third proportional to 256.50 and 398.25 is: 618.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.50 : 398.25 = 398.25 : x
  2. Step 2: Convert to fraction form
    256.50/398.25 = 398.25/x
  3. Step 3: Cross multiply
    256.50x = 398.25 × 398.25
  4. Step 4: Simplify right side
    256.50x = 158,603.06
  5. Step 5: Solve for x
    x = 158,603.06/256.50
  6. Step 6: Final answer
    x = 618.34

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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.