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Finding the Third Proportional to 320 and 421.75

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Solution

The third proportional to 320 and 421.75 is: 555.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    320 : 421.75 = 421.75 : x
  2. Step 2: Convert to fraction form
    320/421.75 = 421.75/x
  3. Step 3: Cross multiply
    320x = 421.75 × 421.75
  4. Step 4: Simplify right side
    320x = 177,873.06
  5. Step 5: Solve for x
    x = 177,873.06/320
  6. Step 6: Final answer
    x = 555.85

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Why These Related Problems?

These problems maintain the same ratio (1.32) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.