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Finding the Fourth Proportional to 905.75, 1,249.94 and 491.75

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Solution

The fourth proportional to 905.75, 1,249.94 and 491.75 is: 678.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.75 : 1,249.94 = 491.75 : x
  2. Step 2: Convert to fraction form
    905.75/1,249.94 = 491.75/x
  3. Step 3: Cross multiply
    905.75x = 1,249.94 × 491.75
  4. Step 4: Simplify right side
    905.75x = 614,655.54
  5. Step 5: Solve for x
    x = 614,655.54/905.75
  6. Step 6: Final answer
    x = 678.62

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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.