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Finding the Fourth Proportional to 681.25, 940.21 and 405.25

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Solution

The fourth proportional to 681.25, 940.21 and 405.25 is: 559.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.25 : 940.21 = 405.25 : x
  2. Step 2: Convert to fraction form
    681.25/940.21 = 405.25/x
  3. Step 3: Cross multiply
    681.25x = 940.21 × 405.25
  4. Step 4: Simplify right side
    681.25x = 381,020.10
  5. Step 5: Solve for x
    x = 381,020.10/681.25
  6. Step 6: Final answer
    x = 559.30

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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.