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Finding the Third Proportional to 78 and 136.50

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Solution

The third proportional to 78 and 136.50 is: 238.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    78 : 136.50 = 136.50 : x
  2. Step 2: Convert to fraction form
    78/136.50 = 136.50/x
  3. Step 3: Cross multiply
    78x = 136.50 × 136.50
  4. Step 4: Simplify right side
    78x = 18,632.25
  5. Step 5: Solve for x
    x = 18,632.25/78
  6. Step 6: Final answer
    x = 238.88

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Why These Related Problems?

These problems maintain the same ratio (1.75) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.