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Finding the Fourth Proportional to 621.45, 857.25 and 388.71

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Solution

The fourth proportional to 621.45, 857.25 and 388.71 is: 536.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.45 : 857.25 = 388.71 : x
  2. Step 2: Convert to fraction form
    621.45/857.25 = 388.71/x
  3. Step 3: Cross multiply
    621.45x = 857.25 × 388.71
  4. Step 4: Simplify right side
    621.45x = 333,221.65
  5. Step 5: Solve for x
    x = 333,221.65/621.45
  6. Step 6: Final answer
    x = 536.20

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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.