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Finding the Fourth Proportional to 857.08, 1,285.68 and 309.40

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Solution

The fourth proportional to 857.08, 1,285.68 and 309.40 is: 464.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.08 : 1,285.68 = 309.40 : x
  2. Step 2: Convert to fraction form
    857.08/1,285.68 = 309.40/x
  3. Step 3: Cross multiply
    857.08x = 1,285.68 × 309.40
  4. Step 4: Simplify right side
    857.08x = 397,789.39
  5. Step 5: Solve for x
    x = 397,789.39/857.08
  6. Step 6: Final answer
    x = 464.12

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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.