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Finding the Third Proportional to 138.75 and 312.75

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Solution

The third proportional to 138.75 and 312.75 is: 704.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.75 : 312.75 = 312.75 : x
  2. Step 2: Convert to fraction form
    138.75/312.75 = 312.75/x
  3. Step 3: Cross multiply
    138.75x = 312.75 × 312.75
  4. Step 4: Simplify right side
    138.75x = 97,812.56
  5. Step 5: Solve for x
    x = 97,812.56/138.75
  6. Step 6: Final answer
    x = 704.96

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Why These Related Problems?

These problems maintain the same ratio (2.25) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.