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Finding the Third Proportional to 115 and 280

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Solution

The third proportional to 115 and 280 is: 681.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    115 : 280 = 280 : x
  2. Step 2: Convert to fraction form
    115/280 = 280/x
  3. Step 3: Cross multiply
    115x = 280 × 280
  4. Step 4: Simplify right side
    115x = 78,400
  5. Step 5: Solve for x
    x = 78,400/115
  6. Step 6: Final answer
    x = 681.74

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Why These Related Problems?

These problems maintain the same ratio (2.43) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.