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Finding the Third Proportional to 399.75 and 720.75

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Solution

The third proportional to 399.75 and 720.75 is: 1,299.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.75 : 720.75 = 720.75 : x
  2. Step 2: Convert to fraction form
    399.75/720.75 = 720.75/x
  3. Step 3: Cross multiply
    399.75x = 720.75 × 720.75
  4. Step 4: Simplify right side
    399.75x = 519,480.56
  5. Step 5: Solve for x
    x = 519,480.56/399.75
  6. Step 6: Final answer
    x = 1,299.51

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Why These Related Problems?

These problems maintain the same ratio (1.80) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.