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Finding the Fourth Proportional to 857.20, 1,286.16 and 641.20

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Solution

The fourth proportional to 857.20, 1,286.16 and 641.20 is: 962.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.20 : 1,286.16 = 641.20 : x
  2. Step 2: Convert to fraction form
    857.20/1,286.16 = 641.20/x
  3. Step 3: Cross multiply
    857.20x = 1,286.16 × 641.20
  4. Step 4: Simplify right side
    857.20x = 824,685.79
  5. Step 5: Solve for x
    x = 824,685.79/857.20
  6. Step 6: Final answer
    x = 962.07

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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.