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Finding the Fourth Proportional to 857.29, 1,285.98 and 280.21

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Solution

The fourth proportional to 857.29, 1,285.98 and 280.21 is: 420.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.29 : 1,285.98 = 280.21 : x
  2. Step 2: Convert to fraction form
    857.29/1,285.98 = 280.21/x
  3. Step 3: Cross multiply
    857.29x = 1,285.98 × 280.21
  4. Step 4: Simplify right side
    857.29x = 360,344.46
  5. Step 5: Solve for x
    x = 360,344.46/857.29
  6. Step 6: Final answer
    x = 420.33

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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.