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Finding the Third Proportional to 321 and 355

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Solution

The third proportional to 321 and 355 is: 392.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    321 : 355 = 355 : x
  2. Step 2: Convert to fraction form
    321/355 = 355/x
  3. Step 3: Cross multiply
    321x = 355 × 355
  4. Step 4: Simplify right side
    321x = 126,025
  5. Step 5: Solve for x
    x = 126,025/321
  6. Step 6: Final answer
    x = 392.60

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Why These Related Problems?

These problems maintain the same ratio (1.11) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.