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Finding the Third Proportional to 309,312 and 678,408

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Solution

The third proportional to 309,312 and 678,408 is: 1,487,939.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    309,312 : 678,408 = 678,408 : x
  2. Step 2: Convert to fraction form
    309,312/678,408 = 678,408/x
  3. Step 3: Cross multiply
    309,312x = 678,408 × 678,408
  4. Step 4: Simplify right side
    309,312x = 460,237,414,464
  5. Step 5: Solve for x
    x = 460,237,414,464/309,312
  6. Step 6: Final answer
    x = 1,487,939.09

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Why These Related Problems?

These problems maintain the same ratio (2.19) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.