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Finding the Third Proportional to 398.75 and 621.75

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Solution

The third proportional to 398.75 and 621.75 is: 969.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.75 : 621.75 = 621.75 : x
  2. Step 2: Convert to fraction form
    398.75/621.75 = 621.75/x
  3. Step 3: Cross multiply
    398.75x = 621.75 × 621.75
  4. Step 4: Simplify right side
    398.75x = 386,573.06
  5. Step 5: Solve for x
    x = 386,573.06/398.75
  6. Step 6: Final answer
    x = 969.46

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Why These Related Problems?

These problems maintain the same ratio (1.56) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.