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Finding the Third Proportional to 68.75 and 128.50

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Solution

The third proportional to 68.75 and 128.50 is: 240.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.75 : 128.50 = 128.50 : x
  2. Step 2: Convert to fraction form
    68.75/128.50 = 128.50/x
  3. Step 3: Cross multiply
    68.75x = 128.50 × 128.50
  4. Step 4: Simplify right side
    68.75x = 16,512.25
  5. Step 5: Solve for x
    x = 16,512.25/68.75
  6. Step 6: Final answer
    x = 240.18

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Why These Related Problems?

These problems maintain the same ratio (1.87) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.