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Finding the Fourth Proportional to 857.68, 1,287.14 and 641.83

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Solution

The fourth proportional to 857.68, 1,287.14 and 641.83 is: 963.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.68 : 1,287.14 = 641.83 : x
  2. Step 2: Convert to fraction form
    857.68/1,287.14 = 641.83/x
  3. Step 3: Cross multiply
    857.68x = 1,287.14 × 641.83
  4. Step 4: Simplify right side
    857.68x = 826,121.86
  5. Step 5: Solve for x
    x = 826,121.86/857.68
  6. Step 6: Final answer
    x = 963.21

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.