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Finding the Fourth Proportional to 905.79, 1,250.42 and 640.46

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Solution

The fourth proportional to 905.79, 1,250.42 and 640.46 is: 884.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.79 : 1,250.42 = 640.46 : x
  2. Step 2: Convert to fraction form
    905.79/1,250.42 = 640.46/x
  3. Step 3: Cross multiply
    905.79x = 1,250.42 × 640.46
  4. Step 4: Simplify right side
    905.79x = 800,834.54
  5. Step 5: Solve for x
    x = 800,834.54/905.79
  6. Step 6: Final answer
    x = 884.13

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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.