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Finding the Third Proportional to 155 and 321

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Solution

The third proportional to 155 and 321 is: 664.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    155 : 321 = 321 : x
  2. Step 2: Convert to fraction form
    155/321 = 321/x
  3. Step 3: Cross multiply
    155x = 321 × 321
  4. Step 4: Simplify right side
    155x = 103,041
  5. Step 5: Solve for x
    x = 103,041/155
  6. Step 6: Final answer
    x = 664.78

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Why These Related Problems?

These problems maintain the same ratio (2.07) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.