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Finding the Fourth Proportional to 855.45, 1,283.13 and 393.21

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Solution

The fourth proportional to 855.45, 1,283.13 and 393.21 is: 589.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.45 : 1,283.13 = 393.21 : x
  2. Step 2: Convert to fraction form
    855.45/1,283.13 = 393.21/x
  3. Step 3: Cross multiply
    855.45x = 1,283.13 × 393.21
  4. Step 4: Simplify right side
    855.45x = 504,539.55
  5. Step 5: Solve for x
    x = 504,539.55/855.45
  6. Step 6: Final answer
    x = 589.79

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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.