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Finding the Fourth Proportional to 643.90, 888.88 and 620.82

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Solution

The fourth proportional to 643.90, 888.88 and 620.82 is: 857.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.90 : 888.88 = 620.82 : x
  2. Step 2: Convert to fraction form
    643.90/888.88 = 620.82/x
  3. Step 3: Cross multiply
    643.90x = 888.88 × 620.82
  4. Step 4: Simplify right side
    643.90x = 551,830.04
  5. Step 5: Solve for x
    x = 551,830.04/643.90
  6. Step 6: Final answer
    x = 857.01

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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.