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Finding the Third Proportional to 120.75 and 278.63

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Solution

The third proportional to 120.75 and 278.63 is: 642.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.75 : 278.63 = 278.63 : x
  2. Step 2: Convert to fraction form
    120.75/278.63 = 278.63/x
  3. Step 3: Cross multiply
    120.75x = 278.63 × 278.63
  4. Step 4: Simplify right side
    120.75x = 77,631.89
  5. Step 5: Solve for x
    x = 77,631.89/120.75
  6. Step 6: Final answer
    x = 642.91

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Why These Related Problems?

These problems maintain the same ratio (2.31) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.