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Finding the Fourth Proportional to 905.79, 1,249.92 and 512.85

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Solution

The fourth proportional to 905.79, 1,249.92 and 512.85 is: 707.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.79 : 1,249.92 = 512.85 : x
  2. Step 2: Convert to fraction form
    905.79/1,249.92 = 512.85/x
  3. Step 3: Cross multiply
    905.79x = 1,249.92 × 512.85
  4. Step 4: Simplify right side
    905.79x = 641,021.47
  5. Step 5: Solve for x
    x = 641,021.47/905.79
  6. Step 6: Final answer
    x = 707.69

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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.