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Finding the Fourth Proportional to 857.92, 1,287.08 and 280.76

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Solution

The fourth proportional to 857.92, 1,287.08 and 280.76 is: 421.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.92 : 1,287.08 = 280.76 : x
  2. Step 2: Convert to fraction form
    857.92/1,287.08 = 280.76/x
  3. Step 3: Cross multiply
    857.92x = 1,287.08 × 280.76
  4. Step 4: Simplify right side
    857.92x = 361,360.58
  5. Step 5: Solve for x
    x = 361,360.58/857.92
  6. Step 6: Final answer
    x = 421.21

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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.