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Finding the Fourth Proportional to 811.82, 1,120.31 and 438.80

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Solution

The fourth proportional to 811.82, 1,120.31 and 438.80 is: 605.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.82 : 1,120.31 = 438.80 : x
  2. Step 2: Convert to fraction form
    811.82/1,120.31 = 438.80/x
  3. Step 3: Cross multiply
    811.82x = 1,120.31 × 438.80
  4. Step 4: Simplify right side
    811.82x = 491,584.23
  5. Step 5: Solve for x
    x = 491,584.23/811.82
  6. Step 6: Final answer
    x = 605.54

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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.