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Finding the Fourth Proportional to 640.80, 884.40 and 557.60

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Solution

The fourth proportional to 640.80, 884.40 and 557.60 is: 769.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.80 : 884.40 = 557.60 : x
  2. Step 2: Convert to fraction form
    640.80/884.40 = 557.60/x
  3. Step 3: Cross multiply
    640.80x = 884.40 × 557.60
  4. Step 4: Simplify right side
    640.80x = 493,141.44
  5. Step 5: Solve for x
    x = 493,141.44/640.80
  6. Step 6: Final answer
    x = 769.57

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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.