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Finding the Fourth Proportional to 621.56, 857.82 and 388.64

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Solution

The fourth proportional to 621.56, 857.82 and 388.64 is: 536.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.56 : 857.82 = 388.64 : x
  2. Step 2: Convert to fraction form
    621.56/857.82 = 388.64/x
  3. Step 3: Cross multiply
    621.56x = 857.82 × 388.64
  4. Step 4: Simplify right side
    621.56x = 333,383.16
  5. Step 5: Solve for x
    x = 333,383.16/621.56
  6. Step 6: Final answer
    x = 536.37

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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.