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Finding the Third Proportional to 390.38 and 618.75

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Solution

The third proportional to 390.38 and 618.75 is: 980.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.38 : 618.75 = 618.75 : x
  2. Step 2: Convert to fraction form
    390.38/618.75 = 618.75/x
  3. Step 3: Cross multiply
    390.38x = 618.75 × 618.75
  4. Step 4: Simplify right side
    390.38x = 382,851.56
  5. Step 5: Solve for x
    x = 382,851.56/390.38
  6. Step 6: Final answer
    x = 980.73

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Why These Related Problems?

These problems maintain the same ratio (1.59) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.