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Finding the Fourth Proportional to 643.68, 889.20 and 611.28

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Solution

The fourth proportional to 643.68, 889.20 and 611.28 is: 844.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.68 : 889.20 = 611.28 : x
  2. Step 2: Convert to fraction form
    643.68/889.20 = 611.28/x
  3. Step 3: Cross multiply
    643.68x = 889.20 × 611.28
  4. Step 4: Simplify right side
    643.68x = 543,550.18
  5. Step 5: Solve for x
    x = 543,550.18/643.68
  6. Step 6: Final answer
    x = 844.44

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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.