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Finding the Third Proportional to 129.75 and 210.75

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Solution

The third proportional to 129.75 and 210.75 is: 342.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.75 : 210.75 = 210.75 : x
  2. Step 2: Convert to fraction form
    129.75/210.75 = 210.75/x
  3. Step 3: Cross multiply
    129.75x = 210.75 × 210.75
  4. Step 4: Simplify right side
    129.75x = 44,415.56
  5. Step 5: Solve for x
    x = 44,415.56/129.75
  6. Step 6: Final answer
    x = 342.32

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Why These Related Problems?

These problems maintain the same ratio (1.62) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.