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Finding the Fourth Proportional to 857.12, 1,285.70 and 280.04

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Solution

The fourth proportional to 857.12, 1,285.70 and 280.04 is: 420.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.12 : 1,285.70 = 280.04 : x
  2. Step 2: Convert to fraction form
    857.12/1,285.70 = 280.04/x
  3. Step 3: Cross multiply
    857.12x = 1,285.70 × 280.04
  4. Step 4: Simplify right side
    857.12x = 360,047.43
  5. Step 5: Solve for x
    x = 360,047.43/857.12
  6. Step 6: Final answer
    x = 420.07

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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.