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Finding the Fourth Proportional to 857.50, 1,286.25 and 393.88

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Solution

The fourth proportional to 857.50, 1,286.25 and 393.88 is: 590.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.50 : 1,286.25 = 393.88 : x
  2. Step 2: Convert to fraction form
    857.50/1,286.25 = 393.88/x
  3. Step 3: Cross multiply
    857.50x = 1,286.25 × 393.88
  4. Step 4: Simplify right side
    857.50x = 506,628.15
  5. Step 5: Solve for x
    x = 506,628.15/857.50
  6. Step 6: Final answer
    x = 590.82

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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.