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Finding the Fourth Proportional to 855.90, 1,283.28 and 393.05

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Solution

The fourth proportional to 855.90, 1,283.28 and 393.05 is: 589.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.90 : 1,283.28 = 393.05 : x
  2. Step 2: Convert to fraction form
    855.90/1,283.28 = 393.05/x
  3. Step 3: Cross multiply
    855.90x = 1,283.28 × 393.05
  4. Step 4: Simplify right side
    855.90x = 504,394.94
  5. Step 5: Solve for x
    x = 504,394.94/855.90
  6. Step 6: Final answer
    x = 589.32

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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.