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Finding the Third Proportional to 139.50 and 309

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Solution

The third proportional to 139.50 and 309 is: 684.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.50 : 309 = 309 : x
  2. Step 2: Convert to fraction form
    139.50/309 = 309/x
  3. Step 3: Cross multiply
    139.50x = 309 × 309
  4. Step 4: Simplify right side
    139.50x = 95,481
  5. Step 5: Solve for x
    x = 95,481/139.50
  6. Step 6: Final answer
    x = 684.45

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Why These Related Problems?

These problems maintain the same ratio (2.22) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.