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Finding the Fourth Proportional to 902.64, 1,243.86 and 640.20

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Solution

The fourth proportional to 902.64, 1,243.86 and 640.20 is: 882.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    902.64 : 1,243.86 = 640.20 : x
  2. Step 2: Convert to fraction form
    902.64/1,243.86 = 640.20/x
  3. Step 3: Cross multiply
    902.64x = 1,243.86 × 640.20
  4. Step 4: Simplify right side
    902.64x = 796,319.17
  5. Step 5: Solve for x
    x = 796,319.17/902.64
  6. Step 6: Final answer
    x = 882.21

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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.