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Finding the Fourth Proportional to 820.21, 1,131.86 and 456.39

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Solution

The fourth proportional to 820.21, 1,131.86 and 456.39 is: 629.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.21 : 1,131.86 = 456.39 : x
  2. Step 2: Convert to fraction form
    820.21/1,131.86 = 456.39/x
  3. Step 3: Cross multiply
    820.21x = 1,131.86 × 456.39
  4. Step 4: Simplify right side
    820.21x = 516,569.59
  5. Step 5: Solve for x
    x = 516,569.59/820.21
  6. Step 6: Final answer
    x = 629.80

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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.