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Finding the Third Proportional to 209.81 and 390.19

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Solution

The third proportional to 209.81 and 390.19 is: 725.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.81 : 390.19 = 390.19 : x
  2. Step 2: Convert to fraction form
    209.81/390.19 = 390.19/x
  3. Step 3: Cross multiply
    209.81x = 390.19 × 390.19
  4. Step 4: Simplify right side
    209.81x = 152,246.29
  5. Step 5: Solve for x
    x = 152,246.29/209.81
  6. Step 6: Final answer
    x = 725.63

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Why These Related Problems?

These problems maintain the same ratio (1.86) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.