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Finding the Fourth Proportional to 621.21, 857.26 and 355.65

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Solution

The fourth proportional to 621.21, 857.26 and 355.65 is: 490.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.21 : 857.26 = 355.65 : x
  2. Step 2: Convert to fraction form
    621.21/857.26 = 355.65/x
  3. Step 3: Cross multiply
    621.21x = 857.26 × 355.65
  4. Step 4: Simplify right side
    621.21x = 304,885.16
  5. Step 5: Solve for x
    x = 304,885.16/621.21
  6. Step 6: Final answer
    x = 490.79

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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.