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Finding the Fourth Proportional to 905.78, 1,249.97 and 512.79

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Solution

The fourth proportional to 905.78, 1,249.97 and 512.79 is: 707.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.78 : 1,249.97 = 512.79 : x
  2. Step 2: Convert to fraction form
    905.78/1,249.97 = 512.79/x
  3. Step 3: Cross multiply
    905.78x = 1,249.97 × 512.79
  4. Step 4: Simplify right side
    905.78x = 640,969.55
  5. Step 5: Solve for x
    x = 640,969.55/905.78
  6. Step 6: Final answer
    x = 707.65

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.