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Finding the Fourth Proportional to 490.40, 731.92 and 428.48

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Solution

The fourth proportional to 490.40, 731.92 and 428.48 is: 639.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    490.40 : 731.92 = 428.48 : x
  2. Step 2: Convert to fraction form
    490.40/731.92 = 428.48/x
  3. Step 3: Cross multiply
    490.40x = 731.92 × 428.48
  4. Step 4: Simplify right side
    490.40x = 313,613.08
  5. Step 5: Solve for x
    x = 313,613.08/490.40
  6. Step 6: Final answer
    x = 639.50

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.