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Finding the Third Proportional to 815 and 980

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Solution

The third proportional to 815 and 980 is: 1,178.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    815 : 980 = 980 : x
  2. Step 2: Convert to fraction form
    815/980 = 980/x
  3. Step 3: Cross multiply
    815x = 980 × 980
  4. Step 4: Simplify right side
    815x = 960,400
  5. Step 5: Solve for x
    x = 960,400/815
  6. Step 6: Final answer
    x = 1,178.40

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Why These Related Problems?

These problems maintain the same ratio (1.20) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.