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Finding the Third Proportional to 218.75 and 309.75

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Solution

The third proportional to 218.75 and 309.75 is: 438.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.75 : 309.75 = 309.75 : x
  2. Step 2: Convert to fraction form
    218.75/309.75 = 309.75/x
  3. Step 3: Cross multiply
    218.75x = 309.75 × 309.75
  4. Step 4: Simplify right side
    218.75x = 95,945.06
  5. Step 5: Solve for x
    x = 95,945.06/218.75
  6. Step 6: Final answer
    x = 438.61

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Why These Related Problems?

These problems maintain the same ratio (1.42) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.