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Finding the Fourth Proportional to 621.40, 857.41 and 355.79

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Solution

The fourth proportional to 621.40, 857.41 and 355.79 is: 490.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.40 : 857.41 = 355.79 : x
  2. Step 2: Convert to fraction form
    621.40/857.41 = 355.79/x
  3. Step 3: Cross multiply
    621.40x = 857.41 × 355.79
  4. Step 4: Simplify right side
    621.40x = 305,060.16
  5. Step 5: Solve for x
    x = 305,060.16/621.40
  6. Step 6: Final answer
    x = 490.93

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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.