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Finding the Fourth Proportional to 857.30, 1,286.15 and 309.60

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Solution

The fourth proportional to 857.30, 1,286.15 and 309.60 is: 464.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.30 : 1,286.15 = 309.60 : x
  2. Step 2: Convert to fraction form
    857.30/1,286.15 = 309.60/x
  3. Step 3: Cross multiply
    857.30x = 1,286.15 × 309.60
  4. Step 4: Simplify right side
    857.30x = 398,190.49
  5. Step 5: Solve for x
    x = 398,190.49/857.30
  6. Step 6: Final answer
    x = 464.47

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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.