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Finding the Third Proportional to 121.78 and 287.44

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Solution

The third proportional to 121.78 and 287.44 is: 678.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.78 : 287.44 = 287.44 : x
  2. Step 2: Convert to fraction form
    121.78/287.44 = 287.44/x
  3. Step 3: Cross multiply
    121.78x = 287.44 × 287.44
  4. Step 4: Simplify right side
    121.78x = 82,620.32
  5. Step 5: Solve for x
    x = 82,620.32/121.78
  6. Step 6: Final answer
    x = 678.43

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Why These Related Problems?

These problems maintain the same ratio (2.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.